665105657 has 4 divisors (see below), whose sum is σ = 667022736. Its totient is φ = 663188580.

The previous prime is 665105647. The next prime is 665105663. The reversal of 665105657 is 756501566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665105657 - 2⁴ = 665105641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665105627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 958019 + ... + 958712.

It is an arithmetic number, because the mean of its divisors is an integer number (166755684).

Almost surely, 2^665105657 is an apocalyptic number.

It is an amenable number.

665105657 is a deficient number, since it is larger than the sum of its proper divisors (1917079).

665105657 is a wasteful number, since it uses less digits than its factorization.

665105657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1917078.

The product of its (nonzero) digits is 189000, while the sum is 41.

The square root of 665105657 is about 25789.6424364511. The cubic root of 665105657 is about 872.8980980934.

The spelling of 665105657 in words is "six hundred sixty-five million, one hundred five thousand, six hundred fifty-seven".