665640299 has 4 divisors (see below), whose sum is σ = 665746920. Its totient is φ = 665533680.

The previous prime is 665640293. The next prime is 665640307. The reversal of 665640299 is 992046566.

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 665640299 - 2²⁰ = 664591723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665640293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43322 + ... + 56639.

It is an arithmetic number, because the mean of its divisors is an integer number (166436730).

Almost surely, 2^665640299 is an apocalyptic number.

665640299 is a deficient number, since it is larger than the sum of its proper divisors (106621).

665640299 is an equidigital number, since it uses as much as digits as its factorization.

665640299 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106620.

The product of its (nonzero) digits is 699840, while the sum is 47.

The square root of 665640299 is about 25800.0057945730. The cubic root of 665640299 is about 873.1319271036.

The spelling of 665640299 in words is "six hundred sixty-five million, six hundred forty thousand, two hundred ninety-nine".