679991321 has 4 divisors (see below), whose sum is σ = 681138612. Its totient is φ = 678844032.

The previous prime is 679991281. The next prime is 679991327. The reversal of 679991321 is 123199976.

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 152646025 + 527345296 = 12355^2 + 22964^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-679991321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (679991327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 572756 + ... + 573941.

It is an arithmetic number, because the mean of its divisors is an integer number (170284653).

Almost surely, 2^679991321 is an apocalyptic number.

It is an amenable number.

679991321 is a deficient number, since it is larger than the sum of its proper divisors (1147291).

679991321 is a wasteful number, since it uses less digits than its factorization.

679991321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1147290.

The product of its digits is 183708, while the sum is 47.

The square root of 679991321 is about 26076.6432080511. The cubic root of 679991321 is about 879.3621932309.

The spelling of 679991321 in words is "six hundred seventy-nine million, nine hundred ninety-one thousand, three hundred twenty-one".