668728319 has 8 divisors (see below), whose sum is σ = 767600160. Its totient is φ = 570691296.

The previous prime is 668728271. The next prime is 668728321. The reversal of 668728319 is 913827866.

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

It is not a de Polignac number, because 668728319 - 2¹⁶ = 668662783 is a prime.

It is a super-2 number, since 2×668728319² = 894395129265131522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668728349) 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, 206984 + ... + 210189.

It is an arithmetic number, because the mean of its divisors is an integer number (95950020).

Almost surely, 2^668728319 is an apocalyptic number.

668728319 is a deficient number, since it is larger than the sum of its proper divisors (98871841).

668728319 is a wasteful number, since it uses less digits than its factorization.

668728319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417409.

The product of its digits is 870912, while the sum is 50.

The square root of 668728319 is about 25859.7818822975. The cubic root of 668728319 is about 874.4800476607.

The spelling of 668728319 in words is "six hundred sixty-eight million, seven hundred twenty-eight thousand, three hundred nineteen".