21330288 has 90 divisors (see below), whose sum is σ = 69464304. Its totient is φ = 6092352.

The previous prime is 21330271. The next prime is 21330299. The reversal of 21330288 is 88203312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5545 + ... + 8567.

Almost surely, 2^21330288 is an apocalyptic number.

21330288 is a gapful number since it is divisible by the number (28) 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 21330288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34732152).

21330288 is an abundant number, since it is smaller than the sum of its proper divisors (48134016).

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

21330288 is a wasteful number, since it uses less digits than its factorization.

21330288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3051 (or 3035 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21330288 is about 4618.4724747475. The cubic root of 21330288 is about 277.3313121360.

The spelling of 21330288 in words is "twenty-one million, three hundred thirty thousand, two hundred eighty-eight".