22072721 has 4 divisors (see below), whose sum is σ = 24079344. Its totient is φ = 20066100.

The previous prime is 22072703. The next prime is 22072723. The reversal of 22072721 is 12727022.

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 22072721 - 2²² = 17878417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22072723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1003295 + ... + 1003316.

It is an arithmetic number, because the mean of its divisors is an integer number (6019836).

Almost surely, 2^22072721 is an apocalyptic number.

It is an amenable number.

22072721 is a deficient number, since it is larger than the sum of its proper divisors (2006623).

22072721 is a wasteful number, since it uses less digits than its factorization.

22072721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2006622.

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 22072721 is about 4698.1614489074. The cubic root of 22072721 is about 280.5123315446.

Adding to 22072721 its reverse (12727022), we get a palindrome (34799743).

The spelling of 22072721 in words is "twenty-two million, seventy-two thousand, seven hundred twenty-one".