631881337 has 4 divisors (see below), whose sum is σ = 631944180. Its totient is φ = 631818496.

The previous prime is 631881311. The next prime is 631881343. The reversal of 631881337 is 733188136.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 546577641 + 85303696 = 23379^2 + 9236^2 .

It is a 3-Lehmer number, since φ(631881337) divides (631881337-1)³.

It is a cyclic number.

It is not a de Polignac number, because 631881337 - 2²⁷ = 497663609 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 631881337.

It is not an unprimeable number, because it can be changed into a prime (631881037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12568 + ... + 37705.

It is an arithmetic number, because the mean of its divisors is an integer number (157986045).

Almost surely, 2^631881337 is an apocalyptic number.

631881337 is the 12569-th decagonal number.

It is an amenable number.

631881337 is a deficient number, since it is larger than the sum of its proper divisors (62843).

631881337 is a wasteful number, since it uses less digits than its factorization.

631881337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62842.

The product of its digits is 72576, while the sum is 40.

The square root of 631881337 is about 25137.2499888114. The cubic root of 631881337 is about 858.1143727610.

The spelling of 631881337 in words is "six hundred thirty-one million, eight hundred eighty-one thousand, three hundred thirty-seven".