31561222475491 has 2 divisors, whose sum is σ = 31561222475492. Its totient is φ = 31561222475490.

The previous prime is 31561222475477. The next prime is 31561222475521. The reversal of 31561222475491 is 19457422216513.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31561222475491 - 2⁵ = 31561222475459 is a prime.

It is a super-2 number, since 2×31561222475491² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31561222475441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15780611237745 + 15780611237746.

It is an arithmetic number, because the mean of its divisors is an integer number (15780611237746).

Almost surely, 2^{31561222475491} is an apocalyptic number.

31561222475491 is a deficient number, since it is larger than the sum of its proper divisors (1).

31561222475491 is an equidigital number, since it uses as much as digits as its factorization.

31561222475491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3628800, while the sum is 52.

The spelling of 31561222475491 in words is "thirty-one trillion, five hundred sixty-one billion, two hundred twenty-two million, four hundred seventy-five thousand, four hundred ninety-one".