631516901 has 4 divisors (see below), whose sum is σ = 668664972. Its totient is φ = 594368832.

The previous prime is 631516811. The next prime is 631516913. The reversal of 631516901 is 109615136.

It is a happy number.

631516901 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 25130²+1.

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

It can be written as a sum of positive squares in 2 ways, for example, as 491686276 + 139830625 = 22174^2 + 11825^2 .

It is a cyclic number.

It is not a de Polignac number, because 631516901 - 2¹⁰ = 631515877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631516961) 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, 18574010 + ... + 18574043.

It is an arithmetic number, because the mean of its divisors is an integer number (167166243).

Almost surely, 2^631516901 is an apocalyptic number.

It is an amenable number.

631516901 is a deficient number, since it is larger than the sum of its proper divisors (37148071).

631516901 is a wasteful number, since it uses less digits than its factorization.

631516901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37148070.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 631516901 is about 25130.0000198965. Note that the first 4 decimals coincide. The cubic root of 631516901 is about 857.9493692537.

The spelling of 631516901 in words is "six hundred thirty-one million, five hundred sixteen thousand, nine hundred one".