22788721 has 8 divisors (see below), whose sum is σ = 24173640. Its totient is φ = 21408768.

The previous prime is 22788713. The next prime is 22788737. The reversal of 22788721 is 12788722.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8643600 + 14145121 = 2940^2 + 3761^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 22788721 - 2³ = 22788713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22788761) 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, 12925 + ... + 14581.

It is an arithmetic number, because the mean of its divisors is an integer number (3021705).

Almost surely, 2^22788721 is an apocalyptic number.

It is an amenable number.

22788721 is a deficient number, since it is larger than the sum of its proper divisors (1384919).

22788721 is a wasteful number, since it uses less digits than its factorization.

22788721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2483.

The product of its digits is 25088, while the sum is 37.

The square root of 22788721 is about 4773.7533451154. The cubic root of 22788721 is about 283.5132217124.

Subtracting from 22788721 its reverse (12788722), we obtain a palindrome (9999999).

The spelling of 22788721 in words is "twenty-two million, seven hundred eighty-eight thousand, seven hundred twenty-one".