131 (one hundred [and] thirty-one) is the natural number following 130 and preceding 132. In mathematics 131 is a Sophie Germain prime, an irregular prime, the second 3-digit palindromic prime, and also a permutable prime with 113 and 311. It can be expressed as the sum of three consecutive primes, 131 = 41 + 43 + 47. 131 is an Eisenstein prime with no imaginary part and real part of the form . Because the next odd number, 133, is a semiprime, 131 is a Chen prime. 131 is an Ulam number. 131 is a full reptend prime in base 10 (and also in base 2). The decimal expansion of 1/131 repeats the digits 007633587786259541984732824427480916030534351145038167938931 297709923664122137404580152671755725190839694656488549618320 6106870229 indefinitely. In the military Convair C-131 Samaritan was an American military transport produced from 1954 to 1956 Strike Fighter Squadron (VFA-131) is a United States Navy F/A-18C Hornet fighter squadron stationed at Naval Air Station Oceana Tiger 131 is a German Tiger I heavy tank captured in Tunisia by the British 48th Royal Tank Regiment during World War II was a Mission Buenaventura-class fleet oiler during World War II was a is a United States Navy ship during World War II was a United States Navy was a United States Navy General G. O. Squier-class transport ship during World War II was a United States Navy during World War II was a United States Navy during World War II was a ship of the United States Navy during World War II ZIL-131 is a 3.5-ton 6x6 army truck In transportation London Buses route 131 is a Transport for London contracted bus route in London The Fiat 131 Mirafiori small/medium family car produced from 1974 to 1984 STS-131 is a NASA Contingency Logistic Flight (CLF) of the Space Shuttle Atlantis which launched in April 2010 In other fields 131 is also: The year AD 131 or 131 BC 131 AH is a year in the Islamic calendar that corresponds to 748 – 749 CE. 131 Vala is an inner main belt asteroid Iodine-131, or radioiodine, is a radioisotope of iodine for medical and pharmaceutical use ACP-131 is the controlling publication for listing of Q codes and Z codes, as published by NATO Allied countries Sonnet 131 by William Shakespeare 131 is the medical emergency telephone number in Chile United States Citizenship and Immigration Services Form I-131 to apply for a travel document, reentry permit,