31608561 has 16 divisors (see below), whose sum is σ = 44126208. Its totient is φ = 20101200.

The previous prime is 31608529. The next prime is 31608587. The reversal of 31608561 is 16580613.

It is not a de Polignac number, because 31608561 - 2⁵ = 31608529 is a prime.

It is a super-2 number, since 2×31608561² = 1998202256981442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31608061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4210 + ... + 8996.

It is an arithmetic number, because the mean of its divisors is an integer number (2757888).

Almost surely, 2^31608561 is an apocalyptic number.

31608561 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

31608561 is a deficient number, since it is larger than the sum of its proper divisors (12517647).

31608561 is a wasteful number, since it uses less digits than its factorization.

31608561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4892.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 31608561 is about 5622.1491442330. The cubic root of 31608561 is about 316.1803735756.

The spelling of 31608561 in words is "thirty-one million, six hundred eight thousand, five hundred sixty-one".