31722561 has 48 divisors (see below), whose sum is σ = 53660880. Its totient is φ = 17879040.

The previous prime is 31722553. The next prime is 31722599. The reversal of 31722561 is 16522713.

It is a happy number.

31722561 is a `hidden beast` number, since 31 + 72 + 2 + 561 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 6471936 + 25250625 = 2544^2 + 5025^2 .

It is not a de Polignac number, because 31722561 - 2³ = 31722553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31722521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 81355 + ... + 81743.

It is an arithmetic number, because the mean of its divisors is an integer number (1117935).

Almost surely, 2^31722561 is an apocalyptic number.

It is an amenable number.

31722561 is a deficient number, since it is larger than the sum of its proper divisors (21938319).

31722561 is a wasteful number, since it uses less digits than its factorization.

31722561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466 (or 463 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 31722561 is about 5632.2784909839. The cubic root of 31722561 is about 316.5600314392.

The spelling of 31722561 in words is "thirty-one million, seven hundred twenty-two thousand, five hundred sixty-one".