665718769 has 4 divisors (see below), whose sum is σ = 687193600. Its totient is φ = 644243940.

The previous prime is 665718749. The next prime is 665718829. The reversal of 665718769 is 967817566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665718769 - 2⁵ = 665718737 is a prime.

It is a super-2 number, since 2×665718769² = 886362958797750722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665718709) 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, 10737369 + ... + 10737430.

It is an arithmetic number, because the mean of its divisors is an integer number (171798400).

Almost surely, 2^665718769 is an apocalyptic number.

It is an amenable number.

665718769 is a deficient number, since it is larger than the sum of its proper divisors (21474831).

665718769 is a wasteful number, since it uses less digits than its factorization.

665718769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21474830.

The product of its digits is 3810240, while the sum is 55.

The square root of 665718769 is about 25801.5264858496. The cubic root of 665718769 is about 873.1662359089.

The spelling of 665718769 in words is "six hundred sixty-five million, seven hundred eighteen thousand, seven hundred sixty-nine".