631881261601 has 2 divisors, whose sum is σ = 631881261602. Its totient is φ = 631881261600.

The previous prime is 631881261563. The next prime is 631881261617. The reversal of 631881261601 is 106162188136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 577136493025 + 54744768576 = 759695^2 + 233976^2 .

It is a cyclic number.

It is not a de Polignac number, because 631881261601 - 2²⁹ = 631344390689 is a prime.

It is not a weakly prime, because it can be changed into another prime (631881265601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315940630800 + 315940630801.

It is an arithmetic number, because the mean of its divisors is an integer number (315940630801).

Almost surely, 2^631881261601 is an apocalyptic number.

It is an amenable number.

631881261601 is a deficient number, since it is larger than the sum of its proper divisors (1).

631881261601 is an equidigital number, since it uses as much as digits as its factorization.

631881261601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 43.

The spelling of 631881261601 in words is "six hundred thirty-one billion, eight hundred eighty-one million, two hundred sixty-one thousand, six hundred one".