521713644 has 12 divisors (see below), whose sum is σ = 1217331864. Its totient is φ = 173904544.

The previous prime is 521713637. The next prime is 521713649. The reversal of 521713644 is 446317125.

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

It is not an unprimeable number, because it can be changed into a prime (521713649) 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, 21738057 + ... + 21738080.

It is an arithmetic number, because the mean of its divisors is an integer number (101444322).

Almost surely, 2^521713644 is an apocalyptic number.

It is an amenable number.

521713644 is an abundant number, since it is smaller than the sum of its proper divisors (695618220).

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

521713644 is a wasteful number, since it uses less digits than its factorization.

521713644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43476144 (or 43476142 counting only the distinct ones).

The product of its digits is 20160, while the sum is 33.

The square root of 521713644 is about 22841.0517270987. The cubic root of 521713644 is about 805.0275283463.

The spelling of 521713644 in words is "five hundred twenty-one million, seven hundred thirteen thousand, six hundred forty-four".