20644818 has 16 divisors (see below), whose sum is σ = 41669760. Its totient is φ = 6818256.

The previous prime is 20644807. The next prime is 20644831. The reversal of 20644818 is 81844602.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15130 + ... + 16437.

It is an arithmetic number, because the mean of its divisors is an integer number (2604360).

Almost surely, 2^20644818 is an apocalyptic number.

20644818 is an abundant number, since it is smaller than the sum of its proper divisors (21024942).

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

20644818 is a wasteful number, since it uses less digits than its factorization.

20644818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31681.

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 20644818 is about 4543.6568972580. The cubic root of 20644818 is about 274.3281361872.

The spelling of 20644818 in words is "twenty million, six hundred forty-four thousand, eight hundred eighteen".