31265561 has 4 divisors (see below), whose sum is σ = 31312692. Its totient is φ = 31218432.

The previous prime is 31265551. The next prime is 31265581. The reversal of 31265561 is 16556213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16556213 = 167 ⋅99139.

It can be written as a sum of positive squares in 2 ways, for example, as 18705625 + 12559936 = 4325^2 + 3544^2 .

It is a cyclic number.

It is not a de Polignac number, because 31265561 - 2⁶ = 31265497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31265501) 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, 22556 + ... + 23901.

It is an arithmetic number, because the mean of its divisors is an integer number (7828173).

Almost surely, 2^31265561 is an apocalyptic number.

It is an amenable number.

31265561 is a deficient number, since it is larger than the sum of its proper divisors (47131).

31265561 is an equidigital number, since it uses as much as digits as its factorization.

31265561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47130.

The product of its digits is 5400, while the sum is 29.

The square root of 31265561 is about 5591.5615886799. The cubic root of 31265561 is about 315.0325354821.

The spelling of 31265561 in words is "thirty-one million, two hundred sixty-five thousand, five hundred sixty-one".