399640392 has 40 divisors (see below), whose sum is σ = 1119364950. Its totient is φ = 133213248.

The previous prime is 399640379. The next prime is 399640393. The reversal of 399640392 is 293046993.

It can be written as a sum of positive squares in only one way, i.e., 387066276 + 12574116 = 19674^2 + 3546^2 .

It is not an unprimeable number, because it can be changed into a prime (399640393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 307717 + ... + 309012.

Almost surely, 2^399640392 is an apocalyptic number.

It is an amenable number.

399640392 is an abundant number, since it is smaller than the sum of its proper divisors (719724558).

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

399640392 is a wasteful number, since it uses less digits than its factorization.

399640392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616747 (or 616734 counting only the distinct ones).

The product of its (nonzero) digits is 314928, while the sum is 45.

The square root of 399640392 is about 19991.0077784988. The cubic root of 399640392 is about 736.5854323269.

The spelling of 399640392 in words is "three hundred ninety-nine million, six hundred forty thousand, three hundred ninety-two".