22122221 has 4 divisors (see below), whose sum is σ = 24133344. Its totient is φ = 20111100.

The previous prime is 22122203. The next prime is 22122223. The reversal of 22122221 is 12222122.

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 22122221 - 2¹⁸ = 21860077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22122196 and 22122205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22122223) 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, 1005545 + ... + 1005566.

It is an arithmetic number, because the mean of its divisors is an integer number (6033336).

Almost surely, 2^22122221 is an apocalyptic number.

It is an amenable number.

22122221 is a deficient number, since it is larger than the sum of its proper divisors (2011123).

22122221 is a wasteful number, since it uses less digits than its factorization.

22122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2011122.

The product of its digits is 64, while the sum is 14.

The square root of 22122221 is about 4703.4265169130. The cubic root of 22122221 is about 280.7218661041.

Adding to 22122221 its reverse (12222122), we get a palindrome (34344343).

Subtracting from 22122221 its reverse (12222122), we obtain a palindrome (9900099).

It can be divided in two parts, 22 and 122221, that multiplied together give a palindrome (2688862).

The spelling of 22122221 in words is "twenty-two million, one hundred twenty-two thousand, two hundred twenty-one".