31673561 has 4 divisors (see below), whose sum is σ = 31953972. Its totient is φ = 31393152.

The previous prime is 31673557. The next prime is 31673563. The reversal of 31673561 is 16537613.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3115225 + 28558336 = 1765^2 + 5344^2 .

It is a cyclic number.

It is not a de Polignac number, because 31673561 - 2² = 31673557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31673563) 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, 140036 + ... + 140261.

It is an arithmetic number, because the mean of its divisors is an integer number (7988493).

Almost surely, 2^31673561 is an apocalyptic number.

It is an amenable number.

31673561 is a deficient number, since it is larger than the sum of its proper divisors (280411).

31673561 is a wasteful number, since it uses less digits than its factorization.

31673561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280410.

The product of its digits is 11340, while the sum is 32.

The square root of 31673561 is about 5627.9268829650. The cubic root of 31673561 is about 316.3969568066.

The spelling of 31673561 in words is "thirty-one million, six hundred seventy-three thousand, five hundred sixty-one".