31331023231 has 4 divisors (see below), whose sum is σ = 31333500432. Its totient is φ = 31328546032.

The previous prime is 31331023211. The next prime is 31331023247. The reversal of 31331023231 is 13232013313.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31331023231 - 2⁹ = 31331022719 is a prime.

It is a super-2 number, since 2×31331023231² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31331023211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1219531 + ... + 1244956.

It is an arithmetic number, because the mean of its divisors is an integer number (7833375108).

Almost surely, 2^31331023231 is an apocalyptic number.

31331023231 is a deficient number, since it is larger than the sum of its proper divisors (2477201).

31331023231 is a wasteful number, since it uses less digits than its factorization.

31331023231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2477200.

The product of its (nonzero) digits is 972, while the sum is 22.

Adding to 31331023231 its reverse (13232013313), we get a palindrome (44563036544).

The spelling of 31331023231 in words is "thirty-one billion, three hundred thirty-one million, twenty-three thousand, two hundred thirty-one".