22122720 has 144 divisors (see below), whose sum is σ = 78427440. Its totient is φ = 5889024.

The previous prime is 22122719. The next prime is 22122731. The reversal of 22122720 is 2722122.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

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 = 22122693 and 22122702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38596 + ... + 39164.

It is an arithmetic number, because the mean of its divisors is an integer number (544635).

Almost surely, 2^22122720 is an apocalyptic number.

22122720 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 22122720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39213720).

22122720 is an abundant number, since it is smaller than the sum of its proper divisors (56304720).

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

22122720 is an equidigital number, since it uses as much as digits as its factorization.

22122720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 579 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 22122720 is about 4703.4795630469. The cubic root of 22122720 is about 280.7239767896.

Adding to 22122720 its reverse (2722122), we get a palindrome (24844842).

The spelling of 22122720 in words is "twenty-two million, one hundred twenty-two thousand, seven hundred twenty".