239861905921 has 12 divisors (see below), whose sum is σ = 263669840532. Its totient is φ = 218039756000.

The previous prime is 239861905897. The next prime is 239861905961. The reversal of 239861905921 is 129509168932.

It can be written as a sum of positive squares in 2 ways, for example, as 29254339521 + 210607566400 = 171039^2 + 458920^2 .

It is not a de Polignac number, because 239861905921 - 2⁷ = 239861905793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (239861905961) 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, 1701351 + ... + 1836931.

It is an arithmetic number, because the mean of its divisors is an integer number (21972486711).

Almost surely, 2^239861905921 is an apocalyptic number.

It is an amenable number.

239861905921 is a deficient number, since it is larger than the sum of its proper divisors (23807934611).

239861905921 is a wasteful number, since it uses less digits than its factorization.

239861905921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150224 (or 150213 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 239861905921 in words is "two hundred thirty-nine billion, eight hundred sixty-one million, nine hundred five thousand, nine hundred twenty-one".