631506521 has 2 divisors, whose sum is σ = 631506522. Its totient is φ = 631506520.

The previous prime is 631506517. The next prime is 631506527. The reversal of 631506521 is 125605136.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 469198921 + 162307600 = 21661^2 + 12740^2 .

It is a cyclic number.

It is not a de Polignac number, because 631506521 - 2² = 631506517 is a prime.

It is not a weakly prime, because it can be changed into another prime (631506527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315753260 + 315753261.

It is an arithmetic number, because the mean of its divisors is an integer number (315753261).

Almost surely, 2^631506521 is an apocalyptic number.

It is an amenable number.

631506521 is a deficient number, since it is larger than the sum of its proper divisors (1).

631506521 is an equidigital number, since it uses as much as digits as its factorization.

631506521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 631506521 is about 25129.7934929836. The cubic root of 631506521 is about 857.9446686335.

The spelling of 631506521 in words is "six hundred thirty-one million, five hundred six thousand, five hundred twenty-one".