21115472 has 60 divisors (see below), whose sum is σ = 49702176. Its totient is φ = 8648640.

The previous prime is 21115453. The next prime is 21115511. The reversal of 21115472 is 27451112.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17447 + ... + 18617.

Almost surely, 2^21115472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21115472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24851088).

21115472 is an abundant number, since it is smaller than the sum of its proper divisors (28586704).

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

21115472 is a wasteful number, since it uses less digits than its factorization.

21115472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1216 (or 1203 counting only the distinct ones).

The product of its digits is 560, while the sum is 23.

The square root of 21115472 is about 4595.1574510565. The cubic root of 21115472 is about 276.3971737504.

Adding to 21115472 its reverse (27451112), we get a palindrome (48566584).

The spelling of 21115472 in words is "twenty-one million, one hundred fifteen thousand, four hundred seventy-two".