22121221 has 8 divisors (see below), whose sum is σ = 22714560. Its totient is φ = 21531552.

The previous prime is 22121213. The next prime is 22121293. The reversal of 22121221 is 12212122.

It is a happy number.

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 22121221 - 2³ = 22121213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22121201) 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, 14721 + ... + 16153.

It is an arithmetic number, because the mean of its divisors is an integer number (2839320).

Almost surely, 2^22121221 is an apocalyptic number.

It is an amenable number.

22121221 is a deficient number, since it is larger than the sum of its proper divisors (593339).

22121221 is a wasteful number, since it uses less digits than its factorization.

22121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1835.

The product of its digits is 32, while the sum is 13.

The square root of 22121221 is about 4703.3202102345. The cubic root of 22121221 is about 280.7176361777.

Adding to 22121221 its reverse (12212122), we get a palindrome (34333343).

Subtracting from 22121221 its reverse (12212122), we obtain a palindrome (9909099).

The spelling of 22121221 in words is "twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".