665668505323 has 4 divisors (see below), whose sum is σ = 681904322568. Its totient is φ = 649432688080.

The previous prime is 665668505311. The next prime is 665668505353. The reversal of 665668505323 is 323505866566.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665668505323 is a prime.

It is a super-2 number, since 2×665668505323² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665668505353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8117908561 + ... + 8117908642.

It is an arithmetic number, because the mean of its divisors is an integer number (170476080642).

Almost surely, 2^665668505323 is an apocalyptic number.

665668505323 is a deficient number, since it is larger than the sum of its proper divisors (16235817245).

665668505323 is a wasteful number, since it uses less digits than its factorization.

665668505323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16235817244.

The product of its (nonzero) digits is 23328000, while the sum is 55.

It can be divided in two parts, 665668505 and 323, that added together give a triangular number (665668828 = T₃₆₄₈₇).

The spelling of 665668505323 in words is "six hundred sixty-five billion, six hundred sixty-eight million, five hundred five thousand, three hundred twenty-three".