665817985 has 8 divisors (see below), whose sum is σ = 913121856. Its totient is φ = 456560880.

The previous prime is 665817967. The next prime is 665818001. The reversal of 665817985 is 589718566.

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

It is not a de Polignac number, because 665817985 - 2⁵ = 665817953 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9511651 + ... + 9511720.

It is an arithmetic number, because the mean of its divisors is an integer number (114140232).

Almost surely, 2^665817985 is an apocalyptic number.

It is an amenable number.

665817985 is a deficient number, since it is larger than the sum of its proper divisors (247303871).

665817985 is a wasteful number, since it uses less digits than its factorization.

665817985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19023383.

The product of its digits is 3628800, while the sum is 55.

The square root of 665817985 is about 25803.4490911583. The cubic root of 665817985 is about 873.2096114612.

The spelling of 665817985 in words is "six hundred sixty-five million, eight hundred seventeen thousand, nine hundred eighty-five".