665808566 has 4 divisors (see below), whose sum is σ = 998712852. Its totient is φ = 332904282.

The previous prime is 665808529. The next prime is 665808571.

665808566 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166452140 + ... + 166452143.

It is an arithmetic number, because the mean of its divisors is an integer number (249678213).

Almost surely, 2^665808566 is an apocalyptic number.

665808566 is a deficient number, since it is larger than the sum of its proper divisors (332904286).

665808566 is a wasteful number, since it uses less digits than its factorization.

665808566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332904285.

The product of its (nonzero) digits is 2073600, while the sum is 50.

The square root of 665808566 is about 25803.2665761527. The cubic root of 665808566 is about 873.2054938193.

The spelling of 665808566 in words is "six hundred sixty-five million, eight hundred eight thousand, five hundred sixty-six".