31561432 has 32 divisors (see below), whose sum is σ = 71193600. Its totient is φ = 12813984.

The previous prime is 31561429. The next prime is 31561433. The reversal of 31561432 is 23416513.

It is a super-2 number, since 2×31561432² = 1992247979781248, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31561397 and 31561406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31561433) 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 7 ways as a sum of consecutive naturals, for example, 13768 + ... + 15895.

It is an arithmetic number, because the mean of its divisors is an integer number (2224800).

Almost surely, 2^31561432 is an apocalyptic number.

It is an amenable number.

31561432 is an abundant number, since it is smaller than the sum of its proper divisors (39632168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31561432 is a wasteful number, since it uses less digits than its factorization.

31561432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29695 (or 29691 counting only the distinct ones).

The product of its digits is 2160, while the sum is 25.

The square root of 31561432 is about 5617.9562120045. The cubic root of 31561432 is about 316.0231516446.

Adding to 31561432 its reverse (23416513), we get a palindrome (54977945).

The spelling of 31561432 in words is "thirty-one million, five hundred sixty-one thousand, four hundred thirty-two".