399112111021 has 12 divisors (see below), whose sum is σ = 439152606172. Its totient is φ = 360572617728.

The previous prime is 399112110997. The next prime is 399112111061. The reversal of 399112111021 is 120111211993.

It can be written as a sum of positive squares in 2 ways, for example, as 51854121225 + 347257989796 = 227715^2 + 589286^2 .

It is not a de Polignac number, because 399112111021 - 2²⁹ = 398575240109 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 (399112111061) 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, 6920340 + ... + 6977773.

Almost surely, 2^399112111021 is an apocalyptic number.

It is an amenable number.

399112111021 is a deficient number, since it is larger than the sum of its proper divisors (40040495151).

399112111021 is a wasteful number, since it uses less digits than its factorization.

399112111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13898220 (or 13898173 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 31.

The spelling of 399112111021 in words is "three hundred ninety-nine billion, one hundred twelve million, one hundred eleven thousand, twenty-one".