668399165 has 16 divisors (see below), whose sum is σ = 933959808. Its totient is φ = 449681856.

The previous prime is 668399131. The next prime is 668399177. The reversal of 668399165 is 561993866.

It is a cyclic number.

It is not a de Polignac number, because 668399165 - 2⁶ = 668399101 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 178307 + ... + 182016.

It is an arithmetic number, because the mean of its divisors is an integer number (58372488).

Almost surely, 2^668399165 is an apocalyptic number.

It is an amenable number.

668399165 is a deficient number, since it is larger than the sum of its proper divisors (265560643).

668399165 is a wasteful number, since it uses less digits than its factorization.

668399165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360388.

The product of its digits is 2099520, while the sum is 53.

The square root of 668399165 is about 25853.4168921634. The cubic root of 668399165 is about 874.3365485067.

The spelling of 668399165 in words is "six hundred sixty-eight million, three hundred ninety-nine thousand, one hundred sixty-five".