1396889978 has 16 divisors (see below), whose sum is σ = 2289301920. Its totient is φ = 633982800.

The previous prime is 1396889953. The next prime is 1396889987. The reversal of 1396889978 is 8799886931.

It is a super-2 number, since 2×1396889978² = 3902603221273680968, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33488 + ... + 62571.

It is an arithmetic number, because the mean of its divisors is an integer number (143081370).

Almost surely, 2^1396889978 is an apocalyptic number.

1396889978 is a deficient number, since it is larger than the sum of its proper divisors (892411942).

1396889978 is a wasteful number, since it uses less digits than its factorization.

1396889978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96733.

The product of its digits is 47029248, while the sum is 68.

The square root of 1396889978 is about 37374.9913444806. The cubic root of 1396889978 is about 1117.8599595459.

The spelling of 1396889978 in words is "one billion, three hundred ninety-six million, eight hundred eighty-nine thousand, nine hundred seventy-eight".