665263666 has 8 divisors (see below), whose sum is σ = 1003066524. Its totient is φ = 330908160.

The previous prime is 665263649. The next prime is 665263691. The reversal of 665263666 is 666362566.

It can be written as a sum of positive squares in 2 ways, for example, as 643687641 + 21576025 = 25371^2 + 4645^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 861355 + ... + 862126.

Almost surely, 2^665263666 is an apocalyptic number.

665263666 is a deficient number, since it is larger than the sum of its proper divisors (337802858).

665263666 is a wasteful number, since it uses less digits than its factorization.

665263666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1723676.

The product of its digits is 1399680, while the sum is 46.

The square root of 665263666 is about 25792.7056742793. The cubic root of 665263666 is about 872.9672173545.

The spelling of 665263666 in words is "six hundred sixty-five million, two hundred sixty-three thousand, six hundred sixty-six".