664761599 has 4 divisors (see below), whose sum is σ = 665009520. Its totient is φ = 664513680.

The previous prime is 664761593. The next prime is 664761611. The reversal of 664761599 is 995167466.

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

It is a cyclic number.

It is not a de Polignac number, because 664761599 - 2²⁴ = 647984383 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664761599.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664761593) 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, 119894 + ... + 125315.

It is an arithmetic number, because the mean of its divisors is an integer number (166252380).

Almost surely, 2^664761599 is an apocalyptic number.

664761599 is a deficient number, since it is larger than the sum of its proper divisors (247921).

664761599 is a wasteful number, since it uses less digits than its factorization.

664761599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247920.

The product of its digits is 2449440, while the sum is 53.

The square root of 664761599 is about 25782.9711049755. The cubic root of 664761599 is about 872.7475559091.

The spelling of 664761599 in words is "six hundred sixty-four million, seven hundred sixty-one thousand, five hundred ninety-nine".