20989920 has 96 divisors (see below), whose sum is σ = 75575808. Its totient is φ = 4796928.

The previous prime is 20989919. The next prime is 20989931. The reversal of 20989920 is 2998902.

It is a tau number, because it is divible by the number of its divisors (96).

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, 237 + ... + 6483.

It is an arithmetic number, because the mean of its divisors is an integer number (787248).

Almost surely, 2^20989920 is an apocalyptic number.

20989920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20989920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37787904).

20989920 is an abundant number, since it is smaller than the sum of its proper divisors (54585888).

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

20989920 is a wasteful number, since it uses less digits than its factorization.

20989920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6272 (or 6264 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 20989920 is about 4581.4757447792. The cubic root of 20989920 is about 275.8482677866.

The spelling of 20989920 in words is "twenty million, nine hundred eighty-nine thousand, nine hundred twenty".