636665 has 8 divisors (see below), whose sum is σ = 768768. Its totient is φ = 506160.

The previous prime is 636653. The next prime is 636673. The reversal of 636665 is 566636.

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

It is not a de Polignac number, because 636665 - 2⁸ = 636409 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 830 + ... + 1400.

It is an arithmetic number, because the mean of its divisors is an integer number (96096).

2⁶³⁶⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

636665 is a deficient number, since it is larger than the sum of its proper divisors (132103).

636665 is a wasteful number, since it uses less digits than its factorization.

636665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 799.

The product of its digits is 19440, while the sum is 32.

The square root of 636665 is about 797.9129025151. The cubic root of 636665 is about 86.0274385135.

The spelling of 636665 in words is "six hundred thirty-six thousand, six hundred sixty-five".