665399911 has 8 divisors (see below), whose sum is σ = 726372864. Its totient is φ = 604507320.

The previous prime is 665399899. The next prime is 665399939. The reversal of 665399911 is 119993566.

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

It is a cyclic number.

It is not a de Polignac number, because 665399911 - 2²⁹ = 128528999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665399951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2065 + ... + 36538.

It is an arithmetic number, because the mean of its divisors is an integer number (90796608).

Almost surely, 2^665399911 is an apocalyptic number.

665399911 is a deficient number, since it is larger than the sum of its proper divisors (60972953).

665399911 is a wasteful number, since it uses less digits than its factorization.

665399911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40181.

The product of its digits is 393660, while the sum is 49.

The square root of 665399911 is about 25795.3466927661. The cubic root of 665399911 is about 873.0268074118.

The spelling of 665399911 in words is "six hundred sixty-five million, three hundred ninety-nine thousand, nine hundred eleven".