399861520 has 40 divisors (see below), whose sum is σ = 952360920. Its totient is φ = 156042240.

The previous prime is 399861503. The next prime is 399861533. The reversal of 399861520 is 25168993.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 501264 + 399360256 = 708^2 + 19984^2 .

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, 57675 + ... + 64234.

It is an arithmetic number, because the mean of its divisors is an integer number (23809023).

Almost surely, 2^399861520 is an apocalyptic number.

It is an amenable number.

399861520 is an abundant number, since it is smaller than the sum of its proper divisors (552499400).

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

399861520 is a wasteful number, since it uses less digits than its factorization.

399861520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121963 (or 121957 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 399861520 is about 19996.5377003120. The cubic root of 399861520 is about 736.7212624670.

The spelling of 399861520 in words is "three hundred ninety-nine million, eight hundred sixty-one thousand, five hundred twenty".