665870517 has 32 divisors (see below), whose sum is σ = 1067808000. Its totient is φ = 407664576.

The previous prime is 665870489. The next prime is 665870521. The reversal of 665870517 is 715078566.

665870517 is a `hidden beast` number, since 6 + 65 + 8 + 70 + 517 = 666.

It is not a de Polignac number, because 665870517 - 2⁶ = 665870453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665877517) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65083 + ... + 74615.

It is an arithmetic number, because the mean of its divisors is an integer number (33369000).

Almost surely, 2^665870517 is an apocalyptic number.

It is an amenable number.

665870517 is a deficient number, since it is larger than the sum of its proper divisors (401937483).

665870517 is a wasteful number, since it uses less digits than its factorization.

665870517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9754 (or 9748 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 45.

The square root of 665870517 is about 25804.4669970143. The cubic root of 665870517 is about 873.2325758158.

The spelling of 665870517 in words is "six hundred sixty-five million, eight hundred seventy thousand, five hundred seventeen".