31561222475521 has 2 divisors, whose sum is σ = 31561222475522. Its totient is φ = 31561222475520.

The previous prime is 31561222475491. The next prime is 31561222475527. The reversal of 31561222475521 is 12557422216513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31514582026225 + 46640449296 = 5613785^2 + 215964^2 .

It is a cyclic number.

It is not a de Polignac number, because 31561222475521 - 2¹⁵ = 31561222442753 is a prime.

It is a super-2 number, since 2×31561222475521² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31561222475527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15780611237760 + 15780611237761.

It is an arithmetic number, because the mean of its divisors is an integer number (15780611237761).

Almost surely, 2^{31561222475521} is an apocalyptic number.

It is an amenable number.

31561222475521 is a deficient number, since it is larger than the sum of its proper divisors (1).

31561222475521 is an equidigital number, since it uses as much as digits as its factorization.

31561222475521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008000, while the sum is 46.

The spelling of 31561222475521 in words is "thirty-one trillion, five hundred sixty-one billion, two hundred twenty-two million, four hundred seventy-five thousand, five hundred twenty-one".