import datetime
ts = 856742400
dt = datetime.datetime.utcfromtimestamp(ts)
print(dt) # 1997-02-24 00:00:00const ts = 856742400;
const date = new Date(ts * 1000);
console.log(date.toISOString());
// 1997-02-24T00:00:00.000Zimport java.time.Instant;
import java.time.ZoneOffset;
long ts = 856742400L;
Instant instant = Instant.ofEpochSecond(ts);
System.out.println(instant);
// 1997-02-24T00:00:00.000Z