665677691 has 6 divisors (see below), whose sum is σ = 774359820. Its totient is φ = 570580836.

The previous prime is 665677643. The next prime is 665677697. The reversal of 665677691 is 196776566.

It is not a de Polignac number, because 665677691 - 2⁶ = 665677627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665677697) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6792581 + ... + 6792678.

It is an arithmetic number, because the mean of its divisors is an integer number (129059970).

Almost surely, 2^665677691 is an apocalyptic number.

665677691 is a deficient number, since it is larger than the sum of its proper divisors (108682129).

665677691 is a wasteful number, since it uses less digits than its factorization.

665677691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13585273 (or 13585266 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 53.

The square root of 665677691 is about 25800.7304353966. The cubic root of 665677691 is about 873.1482760425.

The spelling of 665677691 in words is "six hundred sixty-five million, six hundred seventy-seven thousand, six hundred ninety-one".