396939768921 has 24 divisors (see below), whose sum is σ = 596876209760. Its totient is φ = 260659265328.

The previous prime is 396939768919. The next prime is 396939768943. The reversal of 396939768921 is 129867939693.

396939768921 is a `hidden beast` number, since 3 + 96 + 9 + 397 + 68 + 92 + 1 = 666.

It is not a de Polignac number, because 396939768921 - 2¹ = 396939768919 is a prime.

It is a super-2 number, since 2×396939768921² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 396939768921.

It is not an unprimeable number, because it can be changed into a prime (396939768221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26789311 + ... + 26804123.

Almost surely, 2^396939768921 is an apocalyptic number.

It is an amenable number.

396939768921 is a deficient number, since it is larger than the sum of its proper divisors (199936440839).

396939768921 is an frugal number, since it uses more digits than its factorization.

396939768921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29702 (or 14883 counting only the distinct ones).

The product of its digits is 238085568, while the sum is 72.

The spelling of 396939768921 in words is "three hundred ninety-six billion, nine hundred thirty-nine million, seven hundred sixty-eight thousand, nine hundred twenty-one".