631689538 has 4 divisors (see below), whose sum is σ = 947534310. Its totient is φ = 315844768.

The previous prime is 631689529. The next prime is 631689551. The reversal of 631689538 is 835986136.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 411968209 + 219721329 = 20297^2 + 14823^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 631689491 and 631689500.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157922383 + ... + 157922386.

Almost surely, 2^631689538 is an apocalyptic number.

631689538 is a deficient number, since it is larger than the sum of its proper divisors (315844772).

631689538 is a wasteful number, since it uses less digits than its factorization.

631689538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315844771.

The product of its digits is 933120, while the sum is 49.

The square root of 631689538 is about 25133.4346638099. The cubic root of 631689538 is about 858.0275409862.

The spelling of 631689538 in words is "six hundred thirty-one million, six hundred eighty-nine thousand, five hundred thirty-eight".