636645 has 8 divisors (see below), whose sum is σ = 1018656. Its totient is φ = 339536.

The previous prime is 636631. The next prime is 636653. The reversal of 636645 is 546636.

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

It is a cyclic number.

It is not a de Polignac number, because 636645 - 2⁵ = 636613 is a prime.

It is a Curzon number.

It is a plaindrome in base 8.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 636645.

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, 21207 + ... + 21236.

It is an arithmetic number, because the mean of its divisors is an integer number (127332).

2⁶³⁶⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

636645 is a deficient number, since it is larger than the sum of its proper divisors (382011).

636645 is a wasteful number, since it uses less digits than its factorization.

636645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42451.

The product of its digits is 12960, while the sum is 30.

The square root of 636645 is about 797.9003697204. The cubic root of 636645 is about 86.0265376909.

Subtracting from 636645 its reverse (546636), we obtain a palindrome (90009).

The spelling of 636645 in words is "six hundred thirty-six thousand, six hundred forty-five".