21622720 has 112 divisors (see below), whose sum is σ = 60350400. Its totient is φ = 7375872.

The previous prime is 21622693. The next prime is 21622723. The reversal of 21622720 is 2722612.

It is a tau number, because it is divible by the number of its divisors (112).

It is a junction number, because it is equal to n+sod(n) for n = 21622691 and 21622700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21622723) 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 15 ways as a sum of consecutive naturals, for example, 109662 + ... + 109858.

Almost surely, 2^21622720 is an apocalyptic number.

21622720 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 21622720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30175200).

21622720 is an abundant number, since it is smaller than the sum of its proper divisors (38727680).

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

21622720 is an equidigital number, since it uses as much as digits as its factorization.

21622720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21622720 is about 4650.0236558538. The cubic root of 21622720 is about 278.5929410768.

The spelling of 21622720 in words is "twenty-one million, six hundred twenty-two thousand, seven hundred twenty".