21225984 has 80 divisors (see below), whose sum is σ = 60954432. Its totient is φ = 6524928.

The previous prime is 21225973. The next prime is 21225989. The reversal of 21225984 is 48952212.

It is not an unprimeable number, because it can be changed into a prime (21225989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19437 + ... + 20499.

Almost surely, 2^21225984 is an apocalyptic number.

21225984 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 21225984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30477216).

21225984 is an abundant number, since it is smaller than the sum of its proper divisors (39728448).

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

21225984 is a wasteful number, since it uses less digits than its factorization.

21225984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097 (or 1081 counting only the distinct ones).

The product of its digits is 11520, while the sum is 33.

The square root of 21225984 is about 4607.1665913010. The cubic root of 21225984 is about 276.8785280664.

The spelling of 21225984 in words is "twenty-one million, two hundred twenty-five thousand, nine hundred eighty-four".