21622216 has 48 divisors (see below), whose sum is σ = 50944320. Its totient is φ = 8421600.

The previous prime is 21622213. The next prime is 21622219. The reversal of 21622216 is 61222612.

It is an interprime number because it is at equal distance from previous prime (21622213) and next prime (21622219).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21622213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5181 + ... + 8371.

It is an arithmetic number, because the mean of its divisors is an integer number (1061340).

Almost surely, 2^21622216 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 21622216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25472160).

21622216 is an abundant number, since it is smaller than the sum of its proper divisors (29322104).

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

21622216 is a wasteful number, since it uses less digits than its factorization.

21622216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3226 (or 3211 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

The square root of 21622216 is about 4649.9694622653. The cubic root of 21622216 is about 278.5907765028.

Adding to 21622216 its reverse (61222612), we get a palindrome (82844828).

The spelling of 21622216 in words is "twenty-one million, six hundred twenty-two thousand, two hundred sixteen".