399668869520 has 40 divisors (see below), whose sum is σ = 938430438840. Its totient is φ = 158284697600.

The previous prime is 399668869513. The next prime is 399668869577. The reversal of 399668869520 is 25968866993.

It can be written as a sum of positive squares in 4 ways, for example, as 109553056144 + 290115813376 = 330988^2 + 538624^2 .

It is a tau number, because it is divible by the number of its divisors (40).

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, 24723905 + ... + 24740064.

It is an arithmetic number, because the mean of its divisors is an integer number (23460760971).

Almost surely, 2^399668869520 is an apocalyptic number.

It is an amenable number.

399668869520 is an abundant number, since it is smaller than the sum of its proper divisors (538761569320).

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

399668869520 is a wasteful number, since it uses less digits than its factorization.

399668869520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49464083 (or 49464077 counting only the distinct ones).

The product of its (nonzero) digits is 302330880, while the sum is 71.

The spelling of 399668869520 in words is "three hundred ninety-nine billion, six hundred sixty-eight million, eight hundred sixty-nine thousand, five hundred twenty".