31716561 has 4 divisors (see below), whose sum is σ = 42288752. Its totient is φ = 21144372.

The previous prime is 31716557. The next prime is 31716593. The reversal of 31716561 is 16561713.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 31716561 - 2² = 31716557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31716551) 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, 5286091 + ... + 5286096.

It is an arithmetic number, because the mean of its divisors is an integer number (10572188).

Almost surely, 2^31716561 is an apocalyptic number.

It is an amenable number.

31716561 is a deficient number, since it is larger than the sum of its proper divisors (10572191).

31716561 is a wasteful number, since it uses less digits than its factorization.

31716561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10572190.

The product of its digits is 3780, while the sum is 30.

The square root of 31716561 is about 5631.7458216791. The cubic root of 31716561 is about 316.5400721432.

The spelling of 31716561 in words is "thirty-one million, seven hundred sixteen thousand, five hundred sixty-one".