680939621 has 2 divisors, whose sum is σ = 680939622. Its totient is φ = 680939620.

The previous prime is 680939599. The next prime is 680939627. The reversal of 680939621 is 126939086.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 454286596 + 226653025 = 21314^2 + 15055^2 .

It is a cyclic number.

It is not a de Polignac number, because 680939621 - 2¹⁰ = 680938597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (680939627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340469810 + 340469811.

It is an arithmetic number, because the mean of its divisors is an integer number (340469811).

Almost surely, 2^680939621 is an apocalyptic number.

It is an amenable number.

680939621 is a deficient number, since it is larger than the sum of its proper divisors (1).

680939621 is an equidigital number, since it uses as much as digits as its factorization.

680939621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 680939621 is about 26094.8198116025. The cubic root of 680939621 is about 879.7707826726.

The spelling of 680939621 in words is "six hundred eighty million, nine hundred thirty-nine thousand, six hundred twenty-one".