6636 has 24 divisors (see below), whose sum is σ = 17920. Its totient is φ = 1872.

The previous prime is 6619. The next prime is 6637. The reversal of 6636 is 6366.

6636 = T₄₀ + T₄₁ + ... + T₄₆.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6637) 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, 45 + ... + 123.

2⁶⁶³⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8960).

6636 is an abundant number, since it is smaller than the sum of its proper divisors (11284).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6636 is a wasteful number, since it uses less digits than its factorization.

6636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 91 counting only the distinct ones).

The product of its digits is 648, while the sum is 21.

The square root of 6636 is about 81.4616474177. The cubic root of 6636 is about 18.7918177764.

The spelling of 6636 in words is "six thousand, six hundred thirty-six".