22722721 has 16 divisors (see below), whose sum is σ = 27366400. Its totient is φ = 18839520.

The previous prime is 22722719. The next prime is 22722731. The reversal of 22722721 is 12722722.

It is not a de Polignac number, because 22722721 - 2¹ = 22722719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22722701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9565 + ... + 11701.

It is an arithmetic number, because the mean of its divisors is an integer number (1710400).

Almost surely, 2^22722721 is an apocalyptic number.

It is an amenable number.

22722721 is a deficient number, since it is larger than the sum of its proper divisors (4643679).

22722721 is an equidigital number, since it uses as much as digits as its factorization.

22722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2189 (or 2175 counting only the distinct ones).

The product of its digits is 1568, while the sum is 25.

The square root of 22722721 is about 4766.8355331394. The cubic root of 22722721 is about 283.2392562712.

Adding to 22722721 its product of digits (1568), we get a square (22724289 = 4767²).

Subtracting from 22722721 its reverse (12722722), we obtain a palindrome (9999999).

The spelling of 22722721 in words is "twenty-two million, seven hundred twenty-two thousand, seven hundred twenty-one".