21455628 has 24 divisors (see below), whose sum is σ = 51285360. Its totient is φ = 6977280.

The previous prime is 21455593. The next prime is 21455639. The reversal of 21455628 is 82655412.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21313 + ... + 22296.

It is an arithmetic number, because the mean of its divisors is an integer number (2136890).

Almost surely, 2^21455628 is an apocalyptic number.

It is an amenable number.

21455628 is an abundant number, since it is smaller than the sum of its proper divisors (29829732).

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

21455628 is a wasteful number, since it uses less digits than its factorization.

21455628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43657 (or 43655 counting only the distinct ones).

The product of its digits is 19200, while the sum is 33.

The square root of 21455628 is about 4632.0220206730. The cubic root of 21455628 is about 277.8734651795.

The spelling of 21455628 in words is "twenty-one million, four hundred fifty-five thousand, six hundred twenty-eight".