2221122221 has 4 divisors (see below), whose sum is σ = 2221576512. Its totient is φ = 2220667932.

The previous prime is 2221122187. The next prime is 2221122229. The reversal of 2221122221 is 1222211222.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1222211222 = 2 ⋅611105611.

It is a cyclic number.

It is not a de Polignac number, because 2221122221 - 2²² = 2216927917 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2221122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2221122229) 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, 219731 + ... + 229616.

It is an arithmetic number, because the mean of its divisors is an integer number (555394128).

Almost surely, 2^2221122221 is an apocalyptic number.

It is an amenable number.

2221122221 is a deficient number, since it is larger than the sum of its proper divisors (454291).

2221122221 is an equidigital number, since it uses as much as digits as its factorization.

2221122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454290.

The product of its digits is 128, while the sum is 17.

The square root of 2221122221 is about 47128.7833600656. The cubic root of 2221122221 is about 1304.7405268928.

Adding to 2221122221 its reverse (1222211222), we get a palindrome (3443333443).

The spelling of 2221122221 in words is "two billion, two hundred twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".