688653640221 has 16 divisors (see below), whose sum is σ = 949964908800. Its totient is φ = 443225659968.

The previous prime is 688653640211. The next prime is 688653640229. The reversal of 688653640221 is 122046356886.

It is not a de Polignac number, because 688653640221 - 2⁷ = 688653640093 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688653640229) 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, 452460 + ... + 1257786.

It is an arithmetic number, because the mean of its divisors is an integer number (59372806800).

Almost surely, 2^688653640221 is an apocalyptic number.

It is an amenable number.

688653640221 is a deficient number, since it is larger than the sum of its proper divisors (261311268579).

688653640221 is a wasteful number, since it uses less digits than its factorization.

688653640221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815188.

The product of its (nonzero) digits is 3317760, while the sum is 51.

The spelling of 688653640221 in words is "six hundred eighty-eight billion, six hundred fifty-three million, six hundred forty thousand, two hundred twenty-one".