668621080521 has 40 divisors (see below), whose sum is σ = 1004680908000. Its totient is φ = 443126272320.

The previous prime is 668621080493. The next prime is 668621080531. The reversal of 668621080521 is 125080126866.

668621080521 is a `hidden beast` number, since 6 + 68 + 62 + 1 + 0 + 8 + 0 + 521 = 666.

It is not a de Polignac number, because 668621080521 - 2³⁰ = 667547338697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668621080531) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 91325541 + ... + 91332861.

It is an arithmetic number, because the mean of its divisors is an integer number (25117022700).

Almost surely, 2^668621080521 is an apocalyptic number.

It is an amenable number.

668621080521 is a deficient number, since it is larger than the sum of its proper divisors (336059827479).

668621080521 is a wasteful number, since it uses less digits than its factorization.

668621080521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13811 (or 13802 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 668621080521 in words is "six hundred sixty-eight billion, six hundred twenty-one million, eighty thousand, five hundred twenty-one".