31312561 has 8 divisors (see below), whose sum is σ = 36658944. Its totient is φ = 26184480.

The previous prime is 31312549. The next prime is 31312571. The reversal of 31312561 is 16521313.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31312561 - 2⁵ = 31312529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31312571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54265 + ... + 54838.

It is an arithmetic number, because the mean of its divisors is an integer number (4582368).

Almost surely, 2^31312561 is an apocalyptic number.

It is an amenable number.

31312561 is a deficient number, since it is larger than the sum of its proper divisors (5346383).

31312561 is a wasteful number, since it uses less digits than its factorization.

31312561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109151.

The product of its digits is 540, while the sum is 22.

The square root of 31312561 is about 5595.7627719552. The cubic root of 31312561 is about 315.1903141537.

Adding to 31312561 its reverse (16521313), we get a palindrome (47833874).

The spelling of 31312561 in words is "thirty-one million, three hundred twelve thousand, five hundred sixty-one".