521664665131 has 16 divisors (see below), whose sum is σ = 551429176320. Its totient is φ = 492525269280.

The previous prime is 521664665047. The next prime is 521664665167. The reversal of 521664665131 is 131566466125.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 521664665131 - 2¹⁹ = 521664140843 is a prime.

It is a super-2 number, since 2×521664665131² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521664665191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 263746 + ... + 1054936.

It is an arithmetic number, because the mean of its divisors is an integer number (34464323520).

Almost surely, 2^521664665131 is an apocalyptic number.

521664665131 is a deficient number, since it is larger than the sum of its proper divisors (29764511189).

521664665131 is a wasteful number, since it uses less digits than its factorization.

521664665131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 791586.

The product of its digits is 777600, while the sum is 46.

The spelling of 521664665131 in words is "five hundred twenty-one billion, six hundred sixty-four million, six hundred sixty-five thousand, one hundred thirty-one".