20989644 has 48 divisors (see below), whose sum is σ = 53141088. Its totient is φ = 6409728.

The previous prime is 20989627. The next prime is 20989651. The reversal of 20989644 is 44698902.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20989596 and 20989605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24064 + ... + 24920.

It is an arithmetic number, because the mean of its divisors is an integer number (1107106).

Almost surely, 2^20989644 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 20989644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26570544).

20989644 is an abundant number, since it is smaller than the sum of its proper divisors (32151444).

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

20989644 is a wasteful number, since it uses less digits than its factorization.

20989644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034 (or 1032 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 20989644 is about 4581.4456233813. The cubic root of 20989644 is about 275.8470587228.

The spelling of 20989644 in words is "twenty million, nine hundred eighty-nine thousand, six hundred forty-four".