631308312521 has 2 divisors, whose sum is σ = 631308312522. Its totient is φ = 631308312520.

The previous prime is 631308312469. The next prime is 631308312527. The reversal of 631308312521 is 125213803136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 375235879225 + 256072433296 = 612565^2 + 506036^2 .

It is a cyclic number.

It is not a de Polignac number, because 631308312521 - 2⁶ = 631308312457 is a prime.

It is a super-2 number, since 2×631308312521² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (631308312527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315654156260 + 315654156261.

It is an arithmetic number, because the mean of its divisors is an integer number (315654156261).

Almost surely, 2^631308312521 is an apocalyptic number.

It is an amenable number.

631308312521 is a deficient number, since it is larger than the sum of its proper divisors (1).

631308312521 is an equidigital number, since it uses as much as digits as its factorization.

631308312521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 35.

The spelling of 631308312521 in words is "six hundred thirty-one billion, three hundred eight million, three hundred twelve thousand, five hundred twenty-one".