668844729 has 32 divisors (see below), whose sum is σ = 1133895680. Its totient is φ = 381704400.

The previous prime is 668844727. The next prime is 668844739. The reversal of 668844729 is 927448866.

It is not a de Polignac number, because 668844729 - 2¹ = 668844727 is a prime.

It is a super-2 number, since 2×668844729² = 894706543022166882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (668844721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 185514 + ... + 189084.

It is an arithmetic number, because the mean of its divisors is an integer number (35434240).

Almost surely, 2^668844729 is an apocalyptic number.

It is an amenable number.

668844729 is a deficient number, since it is larger than the sum of its proper divisors (465050951).

668844729 is a wasteful number, since it uses less digits than its factorization.

668844729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4578 (or 4572 counting only the distinct ones).

The product of its digits is 4644864, while the sum is 54.

The square root of 668844729 is about 25862.0325767330. The cubic root of 668844729 is about 874.5307869087.

The spelling of 668844729 in words is "six hundred sixty-eight million, eight hundred forty-four thousand, seven hundred twenty-nine".