20644764 has 24 divisors (see below), whose sum is σ = 55052928. Its totient is φ = 5898480.

The previous prime is 20644759. The next prime is 20644807. The reversal of 20644764 is 46744602.

It is a congruent number.

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, 122802 + ... + 122969.

It is an arithmetic number, because the mean of its divisors is an integer number (2293872).

Almost surely, 2^20644764 is an apocalyptic number.

It is an amenable number.

20644764 is an abundant number, since it is smaller than the sum of its proper divisors (34408164).

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

20644764 is a wasteful number, since it uses less digits than its factorization.

20644764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245785 (or 245783 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 33.

The square root of 20644764 is about 4543.6509549040. The cubic root of 20644764 is about 274.3278970032.

The spelling of 20644764 in words is "twenty million, six hundred forty-four thousand, seven hundred sixty-four".