21555268 has 24 divisors (see below), whose sum is σ = 43243200. Its totient is φ = 9209568.

The previous prime is 21555263. The next prime is 21555271. The reversal of 21555268 is 86255512.

It is not an unprimeable number, because it can be changed into a prime (21555263) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9903 + ... + 11881.

It is an arithmetic number, because the mean of its divisors is an integer number (1801800).

Almost surely, 2^21555268 is an apocalyptic number.

21555268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21555268 is an abundant number, since it is smaller than the sum of its proper divisors (21687932).

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

21555268 is a wasteful number, since it uses less digits than its factorization.

21555268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2379 (or 2377 counting only the distinct ones).

The product of its digits is 24000, while the sum is 34.

The square root of 21555268 is about 4642.7651243629. The cubic root of 21555268 is about 278.3029494205.

The spelling of 21555268 in words is "twenty-one million, five hundred fifty-five thousand, two hundred sixty-eight".