21089872 has 20 divisors (see below), whose sum is σ = 41061856. Its totient is φ = 10493280.

The previous prime is 21089863. The next prime is 21089879. The reversal of 21089872 is 27898012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21089879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253 + ... + 6499.

Almost surely, 2^21089872 is an apocalyptic number.

It is an amenable number.

21089872 is a deficient number, since it is larger than the sum of its proper divisors (19971984).

21089872 is a wasteful number, since it uses less digits than its factorization.

21089872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6466 (or 6460 counting only the distinct ones).

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

The square root of 21089872 is about 4592.3710651471. The cubic root of 21089872 is about 276.2854290057.

The spelling of 21089872 in words is "twenty-one million, eighty-nine thousand, eight hundred seventy-two".