636871 has 4 divisors (see below), whose sum is σ = 674352. Its totient is φ = 599392.

The previous prime is 636863. The next prime is 636877. The reversal of 636871 is 178636.

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

It is a cyclic number.

It is not a de Polignac number, because 636871 - 2³ = 636863 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636877) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 18715 + ... + 18748.

It is an arithmetic number, because the mean of its divisors is an integer number (168588).

2⁶³⁶⁸⁷¹ is an apocalyptic number.

636871 is a deficient number, since it is larger than the sum of its proper divisors (37481).

636871 is a wasteful number, since it uses less digits than its factorization.

636871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37480.

The product of its digits is 6048, while the sum is 31.

The square root of 636871 is about 798.0419788457. The cubic root of 636871 is about 86.0367158893.

The spelling of 636871 in words is "six hundred thirty-six thousand, eight hundred seventy-one".