21900288 has 44 divisors (see below), whose sum is σ = 58380440. Its totient is φ = 7299072.

The previous prime is 21900283. The next prime is 21900299. The reversal of 21900288 is 88200912.

It is a super-2 number, since 2×21900288² = 959245228965888, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21900283) 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, 493 + ... + 6636.

Almost surely, 2^21900288 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 21900288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29190220).

21900288 is an abundant number, since it is smaller than the sum of its proper divisors (36480152).

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

21900288 is an equidigital number, since it uses as much as digits as its factorization.

21900288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7152 (or 7134 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 21900288 is about 4679.7743535346. The cubic root of 21900288 is about 279.7799631847.

The spelling of 21900288 in words is "twenty-one million, nine hundred thousand, two hundred eighty-eight".