399432840 has 64 divisors (see below), whose sum is σ = 1199923200. Its totient is φ = 106371072.

The previous prime is 399432829. The next prime is 399432851. The reversal of 399432840 is 48234993.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (399432829) and next prime (399432851).

It is a junction number, because it is equal to n+sod(n) for n = 399432792 and 399432801.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109689 + ... + 113271.

It is an arithmetic number, because the mean of its divisors is an integer number (18748800).

Almost surely, 2^399432840 is an apocalyptic number.

399432840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

399432840 is an abundant number, since it is smaller than the sum of its proper divisors (800490360).

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

399432840 is a wasteful number, since it uses less digits than its factorization.

399432840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4526 (or 4522 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 42.

The square root of 399432840 is about 19985.8159703326. The cubic root of 399432840 is about 736.4578957914.

The spelling of 399432840 in words is "three hundred ninety-nine million, four hundred thirty-two thousand, eight hundred forty".