521663421208 has 16 divisors (see below), whose sum is σ = 1004554561680. Its totient is φ = 253782204768.

The previous prime is 521663421161. The next prime is 521663421229. The reversal of 521663421208 is 802124366125.

It is a congruent 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, 881187916 + ... + 881188507.

It is an arithmetic number, because the mean of its divisors is an integer number (62784660105).

Almost surely, 2^521663421208 is an apocalyptic number.

It is an amenable number.

521663421208 is a deficient number, since it is larger than the sum of its proper divisors (482891140472).

521663421208 is a wasteful number, since it uses less digits than its factorization.

521663421208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1762376466 (or 1762376462 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The spelling of 521663421208 in words is "five hundred twenty-one billion, six hundred sixty-three million, four hundred twenty-one thousand, two hundred eight".