665713123 has 4 divisors (see below), whose sum is σ = 679877280. Its totient is φ = 651548968.

The previous prime is 665713109. The next prime is 665713129. The reversal of 665713123 is 321317566.

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

It is not a de Polignac number, because 665713123 - 2⁹ = 665712611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665713129) 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, 7082008 + ... + 7082101.

It is an arithmetic number, because the mean of its divisors is an integer number (169969320).

Almost surely, 2^665713123 is an apocalyptic number.

665713123 is a deficient number, since it is larger than the sum of its proper divisors (14164157).

665713123 is a wasteful number, since it uses less digits than its factorization.

665713123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14164156.

The product of its digits is 22680, while the sum is 34.

The square root of 665713123 is about 25801.4170734865. The cubic root of 665713123 is about 873.1637674438.

The spelling of 665713123 in words is "six hundred sixty-five million, seven hundred thirteen thousand, one hundred twenty-three".