680745021 has 16 divisors (see below), whose sum is σ = 999433728. Its totient is φ = 408714800.

The previous prime is 680744993. The next prime is 680745029. The reversal of 680745021 is 120547086.

It is a cyclic number.

It is not a de Polignac number, because 680745021 - 2⁷ = 680744893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (680745029) 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, 92865 + ... + 99926.

It is an arithmetic number, because the mean of its divisors is an integer number (62464608).

Almost surely, 2^680745021 is an apocalyptic number.

It is an amenable number.

680745021 is a deficient number, since it is larger than the sum of its proper divisors (318688707).

680745021 is a wasteful number, since it uses less digits than its factorization.

680745021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192912.

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 680745021 is about 26091.0908357623. The cubic root of 680745021 is about 879.6869672600.

The spelling of 680745021 in words is "six hundred eighty million, seven hundred forty-five thousand, twenty-one".