21108984 has 64 divisors (see below), whose sum is σ = 58816800. Its totient is φ = 6268416.

The previous prime is 21108977. The next prime is 21109007. The reversal of 21108984 is 48980112.

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, 7882 + ... + 10214.

Almost surely, 2^21108984 is an apocalyptic number.

21108984 is a gapful number since it is divisible by the number (24) 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 21108984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29408400).

21108984 is an abundant number, since it is smaller than the sum of its proper divisors (37707816).

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

21108984 is a wasteful number, since it uses less digits than its factorization.

21108984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2384 (or 2380 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 21108984 is about 4594.4514362435. The cubic root of 21108984 is about 276.3688619899.

The spelling of 21108984 in words is "twenty-one million, one hundred eight thousand, nine hundred eighty-four".