21897028 has 12 divisors (see below), whose sum is σ = 38359552. Its totient is φ = 10937160.

The previous prime is 21897017. The next prime is 21897053. The reversal of 21897028 is 82079812.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2701 + ... + 7147.

Almost surely, 2^21897028 is an apocalyptic number.

It is an amenable number.

21897028 is a deficient number, since it is larger than the sum of its proper divisors (16462524).

21897028 is a wasteful number, since it uses less digits than its factorization.

21897028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5682 (or 5680 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 21897028 is about 4679.4260331797. The cubic root of 21897028 is about 279.7660801414.

The spelling of 21897028 in words is "twenty-one million, eight hundred ninety-seven thousand, twenty-eight".