21272188 has 24 divisors (see below), whose sum is σ = 43696352. Its totient is φ = 8869824.

The previous prime is 21272183. The next prime is 21272189. The reversal of 21272188 is 88127212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21272183) 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, 9231 + ... + 11302.

Almost surely, 2^21272188 is an apocalyptic number.

21272188 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21272188 is an abundant number, since it is smaller than the sum of its proper divisors (22424164).

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

21272188 is a wasteful number, since it uses less digits than its factorization.

21272188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20581 (or 20579 counting only the distinct ones).

The product of its digits is 3584, while the sum is 31.

The square root of 21272188 is about 4612.1782272588. The cubic root of 21272188 is about 277.0792823925.

The spelling of 21272188 in words is "twenty-one million, two hundred seventy-two thousand, one hundred eighty-eight".