22728561 has 4 divisors (see below), whose sum is σ = 30304752. Its totient is φ = 15152372.

The previous prime is 22728529. The next prime is 22728569. The reversal of 22728561 is 16582722.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 22728561 - 2⁵ = 22728529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (22728569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3788091 + ... + 3788096.

It is an arithmetic number, because the mean of its divisors is an integer number (7576188).

Almost surely, 2^22728561 is an apocalyptic number.

It is an amenable number.

22728561 is a deficient number, since it is larger than the sum of its proper divisors (7576191).

22728561 is an equidigital number, since it uses as much as digits as its factorization.

22728561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7576190.

The product of its digits is 13440, while the sum is 33.

The square root of 22728561 is about 4767.4480594968. The cubic root of 22728561 is about 283.2635194389.

The spelling of 22728561 in words is "twenty-two million, seven hundred twenty-eight thousand, five hundred sixty-one".