21430288 has 20 divisors (see below), whose sum is σ = 45296208. Its totient is φ = 9740960.

The previous prime is 21430259. The next prime is 21430291. The reversal of 21430288 is 88203412.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60706 + ... + 61057.

Almost surely, 2^21430288 is an apocalyptic number.

It is an amenable number.

21430288 is an abundant number, since it is smaller than the sum of its proper divisors (23865920).

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

21430288 is a wasteful number, since it uses less digits than its factorization.

21430288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121782 (or 121776 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 21430288 is about 4629.2859060551. The cubic root of 21430288 is about 277.7640286647.

The spelling of 21430288 in words is "twenty-one million, four hundred thirty thousand, two hundred eighty-eight".