31139979931 has 4 divisors (see below), whose sum is σ = 31159431864. Its totient is φ = 31120528000.

The previous prime is 31139979929. The next prime is 31139979971. The reversal of 31139979931 is 13997993113.

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 31139979931 - 2¹ = 31139979929 is a prime.

It is a super-2 number, since 2×31139979931² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31139979971) 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, 9723565 + ... + 9726766.

It is an arithmetic number, because the mean of its divisors is an integer number (7789857966).

Almost surely, 2^31139979931 is an apocalyptic number.

31139979931 is a deficient number, since it is larger than the sum of its proper divisors (19451933).

31139979931 is a wasteful number, since it uses less digits than its factorization.

31139979931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19451932.

The product of its digits is 1240029, while the sum is 55.

The spelling of 31139979931 in words is "thirty-one billion, one hundred thirty-nine million, nine hundred seventy-nine thousand, nine hundred thirty-one".