20636644 has 36 divisors (see below), whose sum is σ = 42294000. Its totient is φ = 8784720.

The previous prime is 20636621. The next prime is 20636683. The reversal of 20636644 is 44663602.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41107 + ... + 41605.

Almost surely, 2^20636644 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 20636644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21147000).

20636644 is an abundant number, since it is smaller than the sum of its proper divisors (21657356).

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

20636644 is a wasteful number, since it uses less digits than its factorization.

20636644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 728 (or 719 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 31.

The square root of 20636644 is about 4542.7573124700. The cubic root of 20636644 is about 274.2919260643.

The spelling of 20636644 in words is "twenty million, six hundred thirty-six thousand, six hundred forty-four".