665642599 has 16 divisors (see below), whose sum is σ = 743662080. Its totient is φ = 592099200.

The previous prime is 665642573. The next prime is 665642647. The reversal of 665642599 is 995246566.

It is a cyclic number.

It is not a de Polignac number, because 665642599 - 2¹⁵ = 665609831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665642699) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147324 + ... + 151774.

It is an arithmetic number, because the mean of its divisors is an integer number (46478880).

Almost surely, 2^665642599 is an apocalyptic number.

665642599 is a deficient number, since it is larger than the sum of its proper divisors (78019481).

665642599 is a wasteful number, since it uses less digits than its factorization.

665642599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4950.

The product of its digits is 3499200, while the sum is 52.

The square root of 665642599 is about 25800.0503681679. The cubic root of 665642599 is about 873.1329327524.

The spelling of 665642599 in words is "six hundred sixty-five million, six hundred forty-two thousand, five hundred ninety-nine".