21457268 has 24 divisors (see below), whose sum is σ = 43963584. Its totient is φ = 8971200.

The previous prime is 21457253. The next prime is 21457279. The reversal of 21457268 is 86275412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8198 + ... + 10493.

It is an arithmetic number, because the mean of its divisors is an integer number (1831816).

Almost surely, 2^21457268 is an apocalyptic number.

21457268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21457268 is an abundant number, since it is smaller than the sum of its proper divisors (22506316).

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

21457268 is a wasteful number, since it uses less digits than its factorization.

21457268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18743 (or 18741 counting only the distinct ones).

The product of its digits is 26880, while the sum is 35.

The square root of 21457268 is about 4632.1990458097. The cubic root of 21457268 is about 277.8805449206.

The spelling of 21457268 in words is "twenty-one million, four hundred fifty-seven thousand, two hundred sixty-eight".