399604221 has 12 divisors (see below), whose sum is σ = 577506748. Its totient is φ = 266264064.

The previous prime is 399604213. The next prime is 399604301. The reversal of 399604221 is 122406993.

It can be written as a sum of positive squares in 2 ways, for example, as 164025 + 399440196 = 405^2 + 19986^2 .

It is not a de Polignac number, because 399604221 - 2³ = 399604213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399604201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8511 + ... + 29523.

Almost surely, 2^399604221 is an apocalyptic number.

It is an amenable number.

399604221 is a deficient number, since it is larger than the sum of its proper divisors (177902527).

399604221 is a wasteful number, since it uses less digits than its factorization.

399604221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23132 (or 23129 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 399604221 is about 19990.1030762725. The cubic root of 399604221 is about 736.5632091516.

The spelling of 399604221 in words is "three hundred ninety-nine million, six hundred four thousand, two hundred twenty-one".