231479721 has 32 divisors (see below), whose sum is σ = 376905600. Its totient is φ = 139242240.

The previous prime is 231479719. The next prime is 231479737. The reversal of 231479721 is 127974132.

231479721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 231479721 - 2¹ = 231479719 is a prime.

It is a super-2 number, since 2×231479721² = 107165722468475682, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (231479741) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37845 + ... + 43533.

It is an arithmetic number, because the mean of its divisors is an integer number (11778300).

Almost surely, 2^231479721 is an apocalyptic number.

It is an amenable number.

231479721 is a deficient number, since it is larger than the sum of its proper divisors (145425879).

231479721 is a wasteful number, since it uses less digits than its factorization.

231479721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5846 (or 5840 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 231479721 is about 15214.4576308194. The cubic root of 231479721 is about 614.0036932088.

The spelling of 231479721 in words is "two hundred thirty-one million, four hundred seventy-nine thousand, seven hundred twenty-one".