21125188 has 24 divisors (see below), whose sum is σ = 44475200. Its totient is φ = 8576928.

The previous prime is 21125183. The next prime is 21125219. The reversal of 21125188 is 88152112.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21125183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19323 + ... + 20386.

Almost surely, 2^21125188 is an apocalyptic number.

21125188 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21125188 is an abundant number, since it is smaller than the sum of its proper divisors (23350012).

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

21125188 is a wasteful number, since it uses less digits than its factorization.

21125188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39739 (or 39737 counting only the distinct ones).

The product of its digits is 1280, while the sum is 28.

The square root of 21125188 is about 4596.2145293709. The cubic root of 21125188 is about 276.4395607286.

The spelling of 21125188 in words is "twenty-one million, one hundred twenty-five thousand, one hundred eighty-eight".