636689 has 8 divisors (see below), whose sum is σ = 666792. Its totient is φ = 607360.

The previous prime is 636673. The next prime is 636697. The reversal of 636689 is 986636.

It is a happy number.

636689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 146689 + 490000 = 383^2 + 700^2 .

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 636689 - 2⁴ = 636673 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2027 + ... + 2319.

It is an arithmetic number, because the mean of its divisors is an integer number (83349).

2⁶³⁶⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

636689 is a deficient number, since it is larger than the sum of its proper divisors (30103).

636689 is a wasteful number, since it uses less digits than its factorization.

636689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387.

The product of its digits is 46656, while the sum is 38.

The square root of 636689 is about 797.9279416088. The cubic root of 636689 is about 86.0285194758.

The spelling of 636689 in words is "six hundred thirty-six thousand, six hundred eighty-nine".