636881 has 8 divisors (see below), whose sum is σ = 747840. Its totient is φ = 530928.

The previous prime is 636877. The next prime is 636917. The reversal of 636881 is 188636.

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 636881 - 2² = 636877 is a prime.

It is a super-2 number, since 2×636881² = 811234816322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636821) 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, 971 + ... + 1488.

It is an arithmetic number, because the mean of its divisors is an integer number (93480).

2⁶³⁶⁸⁸¹ is an apocalyptic number.

It is an amenable number.

636881 is a deficient number, since it is larger than the sum of its proper divisors (110959).

636881 is a wasteful number, since it uses less digits than its factorization.

636881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2503.

The product of its digits is 6912, while the sum is 32.

The square root of 636881 is about 798.0482441557. The cubic root of 636881 is about 86.0371661964.

The spelling of 636881 in words is "six hundred thirty-six thousand, eight hundred eighty-one".