680721409 has 8 divisors (see below), whose sum is σ = 722358720. Its totient is φ = 640087536.

The previous prime is 680721403. The next prime is 680721413. The reversal of 680721409 is 904127086.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 680721409 - 2¹⁵ = 680688641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680721403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 249462 + ... + 252175.

It is an arithmetic number, because the mean of its divisors is an integer number (90294840).

Almost surely, 2^680721409 is an apocalyptic number.

It is an amenable number.

680721409 is a deficient number, since it is larger than the sum of its proper divisors (41637311).

680721409 is a wasteful number, since it uses less digits than its factorization.

680721409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501719.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 680721409 is about 26090.6383402170. The cubic root of 680721409 is about 879.6767963403.

The spelling of 680721409 in words is "six hundred eighty million, seven hundred twenty-one thousand, four hundred nine".