21544480 has 72 divisors (see below), whose sum is σ = 53862732. Its totient is φ = 8142336.

The previous prime is 21544463. The next prime is 21544487. The reversal of 21544480 is 8444512.

It can be written as a sum of positive squares in 2 ways, for example, as 21492496 + 51984 = 4636^2 + 228^2 .

It is not an unprimeable number, because it can be changed into a prime (21544487) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 57574 + ... + 57946.

Almost surely, 2^21544480 is an apocalyptic number.

21544480 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 21544480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26931366).

21544480 is an abundant number, since it is smaller than the sum of its proper divisors (32318252).

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

21544480 is a wasteful number, since it uses less digits than its factorization.

21544480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 28.

The square root of 21544480 is about 4641.6031713192. The cubic root of 21544480 is about 278.2565132357.

Adding to 21544480 its reverse (8444512), we get a palindrome (29988992).

The spelling of 21544480 in words is "twenty-one million, five hundred forty-four thousand, four hundred eighty".