21730268 has 24 divisors (see below), whose sum is σ = 43663200. Its totient is φ = 9269568.

The previous prime is 21730249. The next prime is 21730273. The reversal of 21730268 is 86203712.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21730268.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4718 + ... + 8106.

It is an arithmetic number, because the mean of its divisors is an integer number (1819300).

Almost surely, 2^21730268 is an apocalyptic number.

21730268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21730268 is an abundant number, since it is smaller than the sum of its proper divisors (21932932).

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

21730268 is a wasteful number, since it uses less digits than its factorization.

21730268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3629 (or 3627 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21730268 is about 4661.5735540695. The cubic root of 21730268 is about 279.0540698468.

The spelling of 21730268 in words is "twenty-one million, seven hundred thirty thousand, two hundred sixty-eight".