636869 has 4 divisors (see below), whose sum is σ = 658860. Its totient is φ = 614880.

The previous prime is 636863. The next prime is 636877. The reversal of 636869 is 968636.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 422500 + 214369 = 650^2 + 463^2 .

It is a cyclic number.

It is not a de Polignac number, because 636869 - 2⁸ = 636613 is a prime.

It is a super-2 number, since 2×636869² = 811204246322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10952 + ... + 11009.

It is an arithmetic number, because the mean of its divisors is an integer number (164715).

2⁶³⁶⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

636869 is a deficient number, since it is larger than the sum of its proper divisors (21991).

636869 is a wasteful number, since it uses less digits than its factorization.

636869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21990.

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

The square root of 636869 is about 798.0407257778. The cubic root of 636869 is about 86.0366258273.

The spelling of 636869 in words is "six hundred thirty-six thousand, eight hundred sixty-nine".