22125721 has 8 divisors (see below), whose sum is σ = 23482440. Its totient is φ = 20775168.

The previous prime is 22125707. The next prime is 22125731. The reversal of 22125721 is 12752122.

It can be written as a sum of positive squares in 4 ways, for example, as 8620096 + 13505625 = 2936^2 + 3675^2 .

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 22125721 - 2⁵ = 22125689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 22125692 and 22125701.

It is not an unprimeable number, because it can be changed into a prime (22125731) 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, 7375 + ... + 9931.

It is an arithmetic number, because the mean of its divisors is an integer number (2935305).

Almost surely, 2^22125721 is an apocalyptic number.

It is an amenable number.

22125721 is a deficient number, since it is larger than the sum of its proper divisors (1356719).

22125721 is a wasteful number, since it uses less digits than its factorization.

22125721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3083.

The product of its digits is 560, while the sum is 22.

The square root of 22125721 is about 4703.7985713676. The cubic root of 22125721 is about 280.7366698425.

Adding to 22125721 its reverse (12752122), we get a palindrome (34877843).

The spelling of 22125721 in words is "twenty-two million, one hundred twenty-five thousand, seven hundred twenty-one".