21815488 has 28 divisors (see below), whose sum is σ = 45838872. Its totient is φ = 10265600.

The previous prime is 21815483. The next prime is 21815527. The reversal of 21815488 is 88451812.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21815483) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8938 + ... + 11113.

Almost surely, 2^21815488 is an apocalyptic number.

It is an amenable number.

21815488 is an abundant number, since it is smaller than the sum of its proper divisors (24023384).

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

21815488 is a wasteful number, since it uses less digits than its factorization.

21815488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20080 (or 20070 counting only the distinct ones).

The product of its digits is 20480, while the sum is 37.

The square root of 21815488 is about 4670.7053000591. The cubic root of 21815488 is about 279.4183845427.

The spelling of 21815488 in words is "twenty-one million, eight hundred fifteen thousand, four hundred eighty-eight".