521631564 has 12 divisors (see below), whose sum is σ = 1217140344. Its totient is φ = 173877184.

The previous prime is 521631563. The next prime is 521631571. The reversal of 521631564 is 465136125.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×521631564² = 544198977122172192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (521631563) 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, 21734637 + ... + 21734660.

It is an arithmetic number, because the mean of its divisors is an integer number (101428362).

Almost surely, 2^521631564 is an apocalyptic number.

It is an amenable number.

521631564 is an abundant number, since it is smaller than the sum of its proper divisors (695508780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521631564 is a wasteful number, since it uses less digits than its factorization.

521631564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43469304 (or 43469302 counting only the distinct ones).

The product of its digits is 21600, while the sum is 33.

The square root of 521631564 is about 22839.2548915239. The cubic root of 521631564 is about 804.9853084262.

Adding to 521631564 its reverse (465136125), we get a palindrome (986767689).

The spelling of 521631564 in words is "five hundred twenty-one million, six hundred thirty-one thousand, five hundred sixty-four".