399031639 has 8 divisors (see below), whose sum is σ = 409086720. Its totient is φ = 388992000.

The previous prime is 399031631. The next prime is 399031657. The reversal of 399031639 is 936130993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399031639 - 2³ = 399031631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399031595 and 399031604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399031631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62602 + ... + 68680.

It is an arithmetic number, because the mean of its divisors is an integer number (51135840).

Almost surely, 2^399031639 is an apocalyptic number.

399031639 is a deficient number, since it is larger than the sum of its proper divisors (10055081).

399031639 is a wasteful number, since it uses less digits than its factorization.

399031639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7721.

The product of its (nonzero) digits is 118098, while the sum is 43.

The square root of 399031639 is about 19975.7763053154. The cubic root of 399031639 is about 736.2112405383.

The spelling of 399031639 in words is "three hundred ninety-nine million, thirty-one thousand, six hundred thirty-nine".