21459984 has 160 divisors (see below), whose sum is σ = 72495360. Its totient is φ = 5326848.

The previous prime is 21459979. The next prime is 21460003. The reversal of 21459984 is 48995412.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1262344 + ... + 1262360.

It is an arithmetic number, because the mean of its divisors is an integer number (453096).

Almost surely, 2^21459984 is an apocalyptic number.

21459984 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 21459984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36247680).

21459984 is an abundant number, since it is smaller than the sum of its proper divisors (51035376).

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

21459984 is a wasteful number, since it uses less digits than its factorization.

21459984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 42 counting only the distinct ones).

The product of its digits is 103680, while the sum is 42.

The square root of 21459984 is about 4632.4922018283. The cubic root of 21459984 is about 277.8922688691.

It can be divided in two parts, 21 and 459984, that multiplied together give a square (9659664 = 3108²).

The spelling of 21459984 in words is "twenty-one million, four hundred fifty-nine thousand, nine hundred eighty-four".