21744480 has 96 divisors (see below), whose sum is σ = 69400800. Its totient is φ = 5722112.

The previous prime is 21744467. The next prime is 21744491. The reversal of 21744480 is 8444712.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 42466 + ... + 42974.

It is an arithmetic number, because the mean of its divisors is an integer number (722925).

Almost surely, 2^21744480 is an apocalyptic number.

21744480 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 21744480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34700400).

21744480 is an abundant number, since it is smaller than the sum of its proper divisors (47656320).

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

21744480 is a wasteful number, since it uses less digits than its factorization.

21744480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616 (or 608 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 30.

The square root of 21744480 is about 4663.0976828713. The cubic root of 21744480 is about 279.1148921088.

The spelling of 21744480 in words is "twenty-one million, seven hundred forty-four thousand, four hundred eighty".