31561172 has 12 divisors (see below), whose sum is σ = 55476960. Its totient is φ = 15710616.

The previous prime is 31561171. The next prime is 31561177. The reversal of 31561172 is 27116513.

It is a super-2 number, since 2×31561172² = 1992215156027168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31561171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16472 + ... + 18287.

It is an arithmetic number, because the mean of its divisors is an integer number (4623080).

Almost surely, 2^31561172 is an apocalyptic number.

It is an amenable number.

31561172 is a deficient number, since it is larger than the sum of its proper divisors (23915788).

31561172 is a wasteful number, since it uses less digits than its factorization.

31561172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34990 (or 34988 counting only the distinct ones).

The product of its digits is 1260, while the sum is 26.

The square root of 31561172 is about 5617.9330718690. The cubic root of 31561172 is about 316.0222838529.

Adding to 31561172 its reverse (27116513), we get a palindrome (58677685).

The spelling of 31561172 in words is "thirty-one million, five hundred sixty-one thousand, one hundred seventy-two".