21226320 has 160 divisors (see below), whose sum is σ = 75709440. Its totient is φ = 5460480.

The previous prime is 21226291. The next prime is 21226321. The reversal of 21226320 is 2362212.

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

It is a junction number, because it is equal to n+sod(n) for n = 21226293 and 21226302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66802 + ... + 67118.

It is an arithmetic number, because the mean of its divisors is an integer number (473184).

Almost surely, 2^21226320 is an apocalyptic number.

21226320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21226320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37854720).

21226320 is an abundant number, since it is smaller than the sum of its proper divisors (54483120).

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

21226320 is a wasteful number, since it uses less digits than its factorization.

21226320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370 (or 358 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21226320 is about 4607.2030560851. The cubic root of 21226320 is about 276.8799890226.

Adding to 21226320 its reverse (2362212), we get a palindrome (23588532).

The spelling of 21226320 in words is "twenty-one million, two hundred twenty-six thousand, three hundred twenty".