21244216 has 32 divisors (see below), whose sum is σ = 46758240. Its totient is φ = 8857728.

The previous prime is 21244213. The next prime is 21244217. The reversal of 21244216 is 61244212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3055 + ... + 7198.

It is an arithmetic number, because the mean of its divisors is an integer number (1461195).

Almost surely, 2^21244216 is an apocalyptic number.

It is an amenable number.

21244216 is an abundant number, since it is smaller than the sum of its proper divisors (25514024).

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

21244216 is a wasteful number, since it uses less digits than its factorization.

21244216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10303 (or 10299 counting only the distinct ones).

The product of its digits is 768, while the sum is 22.

The square root of 21244216 is about 4609.1448230664. The cubic root of 21244216 is about 276.9577800606.

Adding to 21244216 its reverse (61244212), we get a palindrome (82488428).

The spelling of 21244216 in words is "twenty-one million, two hundred forty-four thousand, two hundred sixteen".