I have a dataset like this:

```
df = pd.DataFrame({'name': ['Amy', 'Chris', 'Sam'], 'date': [1.597104e+12, 1.600906e+12, np.nan]})
print(df)

   name          date
0   Amy  1.597104e+12
1 Chris  1.600906e+12
2   Sam           NaT

```

I checked the types of date which shows float64, then I used `pd.to_datetime` to convert it. But I got the result that is not correct.

```
df['date'] = pd.to_datetime(df['date'])
print(df)

    name                     date
0    Amy  1970-01-01 00:26:37.104
1  Chris  1970-01-01 00:26:40.906
2    Sam                      NaT

```

I also tried `df['date'] = pd.to_timedelta(df['date'], unit='d') + pd.to_datetime('1899-12-30')`, but the result below is still incorrect.

```
    name                           date
0    Amy  2055-09-23 23:20:48.000057344
1  Chris  1839-08-30 13:23:48.304879616
2    Sam                            NaT

```

I really have no clue about fixing this, so can someone assist here? Thank you in advance!