31523361625561 has 4 divisors (see below), whose sum is σ = 33948235596772. Its totient is φ = 29098487654352.

The previous prime is 31523361625549. The next prime is 31523361625571. The reversal of 31523361625561 is 16552616332513.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3652089169936 + 27871272455625 = 1911044^2 + 5279325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31523361625561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31523361625571) 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, 1212436985586 + ... + 1212436985611.

It is an arithmetic number, because the mean of its divisors is an integer number (8487058899193).

Almost surely, 2^{31523361625561} is an apocalyptic number.

It is an amenable number.

31523361625561 is a deficient number, since it is larger than the sum of its proper divisors (2424873971211).

31523361625561 is a wasteful number, since it uses less digits than its factorization.

31523361625561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2424873971210.

The product of its digits is 2916000, while the sum is 49.

The spelling of 31523361625561 in words is "thirty-one trillion, five hundred twenty-three billion, three hundred sixty-one million, six hundred twenty-five thousand, five hundred sixty-one".