21226212 has 120 divisors (see below), whose sum is σ = 65049600. Its totient is φ = 6032880.

The previous prime is 21226199. The next prime is 21226213. The reversal of 21226212 is 21262212.

21226212 is a `hidden beast` number, since 21 + 22 + 621 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21226213) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 111037 + ... + 111227.

It is an arithmetic number, because the mean of its divisors is an integer number (542080).

Almost surely, 2^21226212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21226212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32524800).

21226212 is an abundant number, since it is smaller than the sum of its proper divisors (43823388).

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

21226212 is a wasteful number, since it uses less digits than its factorization.

21226212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 203 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 21226212 is about 4607.1913352931. The cubic root of 21226212 is about 276.8795194312.

Adding to 21226212 its reverse (21262212), we get a palindrome (42488424).

The spelling of 21226212 in words is "twenty-one million, two hundred twenty-six thousand, two hundred twelve".