21189227 has 4 divisors (see below), whose sum is σ = 21919920. Its totient is φ = 20458536.

The previous prime is 21189221. The next prime is 21189229. The reversal of 21189227 is 72298112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21189227 - 2⁶ = 21189163 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21189193 and 21189202.

It is not an unprimeable number, because it can be changed into a prime (21189221) 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, 365303 + ... + 365360.

It is an arithmetic number, because the mean of its divisors is an integer number (5479980).

Almost surely, 2^21189227 is an apocalyptic number.

21189227 is a deficient number, since it is larger than the sum of its proper divisors (730693).

21189227 is an equidigital number, since it uses as much as digits as its factorization.

21189227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730692.

The product of its digits is 4032, while the sum is 32.

The square root of 21189227 is about 4603.1757515872. The cubic root of 21189227 is about 276.7186123653.

The spelling of 21189227 in words is "twenty-one million, one hundred eighty-nine thousand, two hundred twenty-seven".