21243222 has 160 divisors (see below), whose sum is σ = 64399104. Its totient is φ = 5054400.

The previous prime is 21243193. The next prime is 21243227. The reversal of 21243222 is 22234212.

21243222 is a `hidden beast` number, since 212 + 432 + 22 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21243195 and 21243204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243227) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 162097 + ... + 162227.

Almost surely, 2^21243222 is an apocalyptic number.

21243222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21243222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32199552).

21243222 is an abundant number, since it is smaller than the sum of its proper divisors (43155882).

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

21243222 is a wasteful number, since it uses less digits than its factorization.

21243222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 167 counting only the distinct ones).

The product of its digits is 384, while the sum is 18.

The square root of 21243222 is about 4609.0369926916. The cubic root of 21243222 is about 276.9534604483.

Adding to 21243222 its reverse (22234212), we get a palindrome (43477434).

It can be divided in two parts, 212 and 43222, that added together give a palindrome (43434).

The spelling of 21243222 in words is "twenty-one million, two hundred forty-three thousand, two hundred twenty-two".