21222320 has 40 divisors (see below), whose sum is σ = 56392224. Its totient is φ = 7276032.

The previous prime is 21222293. The next prime is 21222343. The reversal of 21222320 is 2322212.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21222295 and 21222304.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18389 + ... + 19508.

Almost surely, 2^21222320 is an apocalyptic number.

21222320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222320 is an abundant number, since it is smaller than the sum of its proper divisors (35169904).

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

21222320 is a wasteful number, since it uses less digits than its factorization.

21222320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37917 (or 37911 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21222320 is about 4606.7689327771. The cubic root of 21222320 is about 276.8625956868.

Adding to 21222320 its reverse (2322212), we get a palindrome (23544532).

The spelling of 21222320 in words is "twenty-one million, two hundred twenty-two thousand, three hundred twenty".