521991122668 has 12 divisors (see below), whose sum is σ = 913843697760. Its totient is φ = 260892923312.

The previous prime is 521991122647. The next prime is 521991122683. The reversal of 521991122668 is 866221199125.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25648063 + ... + 25668406.

It is an arithmetic number, because the mean of its divisors is an integer number (76153641480).

Almost surely, 2^521991122668 is an apocalyptic number.

It is an amenable number.

521991122668 is a deficient number, since it is larger than the sum of its proper divisors (391852575092).

521991122668 is a wasteful number, since it uses less digits than its factorization.

521991122668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51319016 (or 51319014 counting only the distinct ones).

The product of its digits is 933120, while the sum is 52.

The spelling of 521991122668 in words is "five hundred twenty-one billion, nine hundred ninety-one million, one hundred twenty-two thousand, six hundred sixty-eight".