import datetime
ts = 669254399
dt = datetime.datetime.utcfromtimestamp(ts)
print(dt) # 1991-03-17 23:59:59const ts = 669254399;
const date = new Date(ts * 1000);
console.log(date.toISOString());
// 1991-03-17T23:59:59.000Zimport java.time.Instant;
import java.time.ZoneOffset;
long ts = 669254399L;
Instant instant = Instant.ofEpochSecond(ts);
System.out.println(instant);
// 1991-03-17T23:59:59.000Z