22081728 has 56 divisors (see below), whose sum is σ = 59692032. Its totient is φ = 7201024.

The previous prime is 22081723. The next prime is 22081733. The reversal of 22081728 is 82718022.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (22081723) and next prime (22081733).

It is a super-2 number, since 2×22081728² = 975205422931968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 22081695 and 22081704.

It is not an unprimeable number, because it can be changed into a prime (22081721) 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, 7801 + ... + 10247.

Almost surely, 2^22081728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22081728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29846016).

22081728 is an abundant number, since it is smaller than the sum of its proper divisors (37610304).

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

22081728 is a wasteful number, since it uses less digits than its factorization.

22081728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2509 (or 2499 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 22081728 is about 4699.1199176016. The cubic root of 22081728 is about 280.5504816664.

The spelling of 22081728 in words is "twenty-two million, eighty-one thousand, seven hundred twenty-eight".