631520842 has 4 divisors (see below), whose sum is σ = 947281266. Its totient is φ = 315760420.

The previous prime is 631520783. The next prime is 631520863. The reversal of 631520842 is 248025136.

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., 448973721 + 182547121 = 21189^2 + 13511^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157880209 + ... + 157880212.

Almost surely, 2^631520842 is an apocalyptic number.

631520842 is a deficient number, since it is larger than the sum of its proper divisors (315760424).

631520842 is a wasteful number, since it uses less digits than its factorization.

631520842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315760423.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 631520842 is about 25130.0784320304. The cubic root of 631520842 is about 857.9511539361.

Adding to 631520842 its reverse (248025136), we get a palindrome (879545978).

The spelling of 631520842 in words is "six hundred thirty-one million, five hundred twenty thousand, eight hundred forty-two".