399221031 has 16 divisors (see below), whose sum is σ = 581349888. Its totient is φ = 241675200.

The previous prime is 399221023. The next prime is 399221063. The reversal of 399221031 is 130122993.

It is a happy number.

It is not a de Polignac number, because 399221031 - 2³ = 399221023 is a prime.

It is a super-2 number, since 2×399221031² = 318754863185405922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 399221031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399223031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24466 + ... + 37376.

It is an arithmetic number, because the mean of its divisors is an integer number (36334368).

Almost surely, 2^399221031 is an apocalyptic number.

399221031 is a deficient number, since it is larger than the sum of its proper divisors (182128857).

399221031 is a wasteful number, since it uses less digits than its factorization.

399221031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13862.

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 399221031 is about 19980.5162846209. The cubic root of 399221031 is about 736.3276978581.

The spelling of 399221031 in words is "three hundred ninety-nine million, two hundred twenty-one thousand, thirty-one".