21226188 has 12 divisors (see below), whose sum is σ = 49527800. Its totient is φ = 7075392.

The previous prime is 21226181. The next prime is 21226189. The reversal of 21226188 is 88162212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21226188² = 901102114022688, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21226181) 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, 884413 + ... + 884436.

Almost surely, 2^21226188 is an apocalyptic number.

It is an amenable number.

21226188 is an abundant number, since it is smaller than the sum of its proper divisors (28301612).

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

21226188 is a wasteful number, since it uses less digits than its factorization.

21226188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768856 (or 1768854 counting only the distinct ones).

The product of its digits is 3072, while the sum is 30.

The square root of 21226188 is about 4607.1887306686. The cubic root of 21226188 is about 276.8794150774.

The spelling of 21226188 in words is "twenty-one million, two hundred twenty-six thousand, one hundred eighty-eight".