21222270 has 64 divisors (see below), whose sum is σ = 57335040. Its totient is φ = 5585184.

The previous prime is 21222269. The next prime is 21222293. The reversal of 21222270 is 7222212.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21937 + ... + 22883.

It is an arithmetic number, because the mean of its divisors is an integer number (895860).

Almost surely, 2^21222270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21222270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28667520).

21222270 is an abundant number, since it is smaller than the sum of its proper divisors (36112770).

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

21222270 is a wasteful number, since it uses less digits than its factorization.

21222270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1046 (or 1040 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21222270 is about 4606.7635059768. The cubic root of 21222270 is about 276.8623782563.

Adding to 21222270 its reverse (7222212), we get a palindrome (28444482).

The spelling of 21222270 in words is "twenty-one million, two hundred twenty-two thousand, two hundred seventy".