21226216 has 16 divisors (see below), whose sum is σ = 43417440. Its totient is φ = 9648240.

The previous prime is 21226213. The next prime is 21226237. The reversal of 21226216 is 61262212.

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

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 120516 + ... + 120691.

It is an arithmetic number, because the mean of its divisors is an integer number (2713590).

Almost surely, 2^21226216 is an apocalyptic number.

It is an amenable number.

21226216 is an abundant number, since it is smaller than the sum of its proper divisors (22191224).

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

21226216 is a wasteful number, since it uses less digits than its factorization.

21226216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241224 (or 241220 counting only the distinct ones).

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

The square root of 21226216 is about 4607.1917693971. The cubic root of 21226216 is about 276.8795368235.

Adding to 21226216 its reverse (61262212), we get a palindrome (82488428).

It can be divided in two parts, 2122 and 6216, that added together give a palindrome (8338).

The spelling of 21226216 in words is "twenty-one million, two hundred twenty-six thousand, two hundred sixteen".