21213088 has 24 divisors (see below), whose sum is σ = 44976708. Its totient is φ = 9790464.

The previous prime is 21213047. The next prime is 21213089. The reversal of 21213088 is 88031212.

It can be written as a sum of positive squares in 2 ways, for example, as 15586704 + 5626384 = 3948^2 + 2372^2 .

It is not an unprimeable number, because it can be changed into a prime (21213089) 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, 25081 + ... + 25912.

Almost surely, 2^21213088 is an apocalyptic number.

It is an amenable number.

21213088 is an abundant number, since it is smaller than the sum of its proper divisors (23763620).

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

21213088 is a wasteful number, since it uses less digits than its factorization.

21213088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51016 (or 51008 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 21213088 is about 4605.7668199769. The cubic root of 21213088 is about 276.8224435231.

The spelling of 21213088 in words is "twenty-one million, two hundred thirteen thousand, eighty-eight".