680321665 has 4 divisors (see below), whose sum is σ = 816386004. Its totient is φ = 544257328.

The previous prime is 680321639. The next prime is 680321689. The reversal of 680321665 is 566123086.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 370139121 + 310182544 = 19239^2 + 17612^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-680321665 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68032162 + ... + 68032171.

It is an arithmetic number, because the mean of its divisors is an integer number (204096501).

Almost surely, 2^680321665 is an apocalyptic number.

It is an amenable number.

680321665 is a deficient number, since it is larger than the sum of its proper divisors (136064339).

680321665 is a wasteful number, since it uses less digits than its factorization.

680321665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136064338.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 680321665 is about 26082.9765364308. The cubic root of 680321665 is about 879.5045700462.

The spelling of 680321665 in words is "six hundred eighty million, three hundred twenty-one thousand, six hundred sixty-five".