521216165660 has 24 divisors (see below), whose sum is σ = 1142143250976. Its totient is φ = 199421837120.

The previous prime is 521216165627. The next prime is 521216165711. The reversal of 521216165660 is 66561612125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566538851 + ... + 566539770.

It is an arithmetic number, because the mean of its divisors is an integer number (47589302124).

Almost surely, 2^521216165660 is an apocalyptic number.

It is an amenable number.

521216165660 is an abundant number, since it is smaller than the sum of its proper divisors (620927085316).

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

521216165660 is a wasteful number, since it uses less digits than its factorization.

521216165660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1133078653 (or 1133078651 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 41.

Adding to 521216165660 its reverse (66561612125), we get a palindrome (587777777785).

The spelling of 521216165660 in words is "five hundred twenty-one billion, two hundred sixteen million, one hundred sixty-five thousand, six hundred sixty".