631688320493 has 2 divisors, whose sum is σ = 631688320494. Its totient is φ = 631688320492.

The previous prime is 631688320463. The next prime is 631688320567. The reversal of 631688320493 is 394023886136.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 586507842244 + 45180478249 = 765838^2 + 212557^2 .

It is a cyclic number.

It is not a de Polignac number, because 631688320493 - 2²⁸ = 631419885037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631688320463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315844160246 + 315844160247.

It is an arithmetic number, because the mean of its divisors is an integer number (315844160247).

Almost surely, 2^631688320493 is an apocalyptic number.

It is an amenable number.

631688320493 is a deficient number, since it is larger than the sum of its proper divisors (1).

631688320493 is an equidigital number, since it uses as much as digits as its factorization.

631688320493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4478976, while the sum is 53.

The spelling of 631688320493 in words is "six hundred thirty-one billion, six hundred eighty-eight million, three hundred twenty thousand, four hundred ninety-three".