631685189 has 2 divisors, whose sum is σ = 631685190. Its totient is φ = 631685188.

The previous prime is 631685177. The next prime is 631685207. The reversal of 631685189 is 981586136.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 608016964 + 23668225 = 24658^2 + 4865^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-631685189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631685389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315842594 + 315842595.

It is an arithmetic number, because the mean of its divisors is an integer number (315842595).

Almost surely, 2^631685189 is an apocalyptic number.

It is an amenable number.

631685189 is a deficient number, since it is larger than the sum of its proper divisors (1).

631685189 is an equidigital number, since it uses as much as digits as its factorization.

631685189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 47.

The square root of 631685189 is about 25133.3481454421. The cubic root of 631685189 is about 858.0255718910.

The spelling of 631685189 in words is "six hundred thirty-one million, six hundred eighty-five thousand, one hundred eighty-nine".