399612816 has 60 divisors (see below), whose sum is σ = 1154449920. Its totient is φ = 128905920.

The previous prime is 399612809. The next prime is 399612821. The reversal of 399612816 is 618216993.

It is a happy number.

It is a super-2 number, since 2×399612816² = 319380805422899712, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40296 + ... + 49223.

It is an arithmetic number, because the mean of its divisors is an integer number (19240832).

Almost surely, 2^399612816 is an apocalyptic number.

399612816 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

399612816 is an abundant number, since it is smaller than the sum of its proper divisors (754837104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399612816 is a wasteful number, since it uses less digits than its factorization.

399612816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89564 (or 89555 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 399612816 is about 19990.3180564993. The cubic root of 399612816 is about 736.5684899728.

The spelling of 399612816 in words is "three hundred ninety-nine million, six hundred twelve thousand, eight hundred sixteen".