631712621 has 2 divisors, whose sum is σ = 631712622. Its totient is φ = 631712620.

The previous prime is 631712603. The next prime is 631712623. The reversal of 631712621 is 126217136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351150121 + 280562500 = 18739^2 + 16750^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-631712621 is a prime.

Together with 631712623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631712623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315856310 + 315856311.

It is an arithmetic number, because the mean of its divisors is an integer number (315856311).

Almost surely, 2^631712621 is an apocalyptic number.

It is an amenable number.

631712621 is a deficient number, since it is larger than the sum of its proper divisors (1).

631712621 is an equidigital number, since it uses as much as digits as its factorization.

631712621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 29.

The square root of 631712621 is about 25133.8938686388. The cubic root of 631712621 is about 858.0379921162.

Adding to 631712621 its reverse (126217136), we get a palindrome (757929757).

The spelling of 631712621 in words is "six hundred thirty-one million, seven hundred twelve thousand, six hundred twenty-one".