399991316920 has 128 divisors (see below), whose sum is σ = 985300848000. Its totient is φ = 145247477760.

The previous prime is 399991316909. The next prime is 399991316947. The reversal of 399991316920 is 29613199993.

It is a super-2 number, since 2×399991316920² (a number of 24 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (61) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15087036 + ... + 15113524.

It is an arithmetic number, because the mean of its divisors is an integer number (7697662875).

Almost surely, 2^399991316920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399991316920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (492650424000).

399991316920 is an abundant number, since it is smaller than the sum of its proper divisors (585309531080).

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

399991316920 is a wasteful number, since it uses less digits than its factorization.

399991316920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26993 (or 26989 counting only the distinct ones).

The product of its (nonzero) digits is 6377292, while the sum is 61.

The spelling of 399991316920 in words is "three hundred ninety-nine billion, nine hundred ninety-one million, three hundred sixteen thousand, nine hundred twenty".