31561979 has 6 divisors (see below), whose sum is σ = 33528084. Its totient is φ = 29705120.

The previous prime is 31561973. The next prime is 31561993. The reversal of 31561979 is 97916513.

It is not a de Polignac number, because 31561979 - 2⁸ = 31561723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31561973) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54317 + ... + 54894.

It is an arithmetic number, because the mean of its divisors is an integer number (5588014).

Almost surely, 2^31561979 is an apocalyptic number.

31561979 is a deficient number, since it is larger than the sum of its proper divisors (1966105).

31561979 is a wasteful number, since it uses less digits than its factorization.

31561979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109245 (or 109228 counting only the distinct ones).

The product of its digits is 51030, while the sum is 41.

The square root of 31561979 is about 5618.0048949783. The cubic root of 31561979 is about 316.0249773292.

The spelling of 31561979 in words is "thirty-one million, five hundred sixty-one thousand, nine hundred seventy-nine".