21530268 has 36 divisors (see below), whose sum is σ = 57289960. Its totient is φ = 6798816.

The previous prime is 21530261. The next prime is 21530281. The reversal of 21530268 is 86203512.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530261) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15055 + ... + 16422.

Almost surely, 2^21530268 is an apocalyptic number.

It is an amenable number.

21530268 is an abundant number, since it is smaller than the sum of its proper divisors (35759692).

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

21530268 is a wasteful number, since it uses less digits than its factorization.

21530268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31506 (or 31501 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21530268 is about 4640.0719822003. The cubic root of 21530268 is about 278.1953150163.

The spelling of 21530268 in words is "twenty-one million, five hundred thirty thousand, two hundred sixty-eight".