21815296 has 28 divisors (see below), whose sum is σ = 43644312. Its totient is φ = 10903552.

The previous prime is 21815291. The next prime is 21815303. The reversal of 21815296 is 69251812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21815291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6861 + ... + 9523.

Almost surely, 2^21815296 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 21815296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21822156).

21815296 is an abundant number, since it is smaller than the sum of its proper divisors (21829016).

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

21815296 is an frugal number, since it uses more digits than its factorization.

21815296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2689 (or 2665 counting only the distinct ones).

The product of its digits is 8640, while the sum is 34.

The square root of 21815296 is about 4670.6847463728. The cubic root of 21815296 is about 279.4175648119.

The spelling of 21815296 in words is "twenty-one million, eight hundred fifteen thousand, two hundred ninety-six".