631312531 has 2 divisors, whose sum is σ = 631312532. Its totient is φ = 631312530.

The previous prime is 631312523. The next prime is 631312559. The reversal of 631312531 is 135213136.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 631312531 - 2³ = 631312523 is a prime.

It is a super-2 number, since 2×631312531² = 797111023595251922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 631312496 and 631312505.

It is not a weakly prime, because it can be changed into another prime (631312501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315656265 + 315656266.

It is an arithmetic number, because the mean of its divisors is an integer number (315656266).

Almost surely, 2^631312531 is an apocalyptic number.

631312531 is a deficient number, since it is larger than the sum of its proper divisors (1).

631312531 is an equidigital number, since it uses as much as digits as its factorization.

631312531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 25.

The square root of 631312531 is about 25125.9334353970. The cubic root of 631312531 is about 857.8568100891.

Adding to 631312531 its reverse (135213136), we get a palindrome (766525667).

The spelling of 631312531 in words is "six hundred thirty-one million, three hundred twelve thousand, five hundred thirty-one".