21089028 has 24 divisors (see below), whose sum is σ = 49446880. Its totient is φ = 6995520.

The previous prime is 21089011. The next prime is 21089051. The reversal of 21089028 is 82098012.

It is a junction number, because it is equal to n+sod(n) for n = 21088986 and 21089004.

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, 1633 + ... + 6696.

Almost surely, 2^21089028 is an apocalyptic number.

It is an amenable number.

21089028 is an abundant number, since it is smaller than the sum of its proper divisors (28357852).

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

21089028 is a wasteful number, since it uses less digits than its factorization.

21089028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8547 (or 8545 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 21089028 is about 4592.2791726985. The cubic root of 21089028 is about 276.2817433818.

The spelling of 21089028 in words is "twenty-one million, eighty-nine thousand, twenty-eight".