2221121221 has 8 divisors (see below), whose sum is σ = 2459206944. Its totient is φ = 1989063120.

The previous prime is 2221121173. The next prime is 2221121239. The reversal of 2221121221 is 1221211222.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2221121221 - 2⁹ = 2221120709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2221121195 and 2221121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2221121521) 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, 1506130 + ... + 1507603.

It is an arithmetic number, because the mean of its divisors is an integer number (307400868).

Almost surely, 2^2221121221 is an apocalyptic number.

It is an amenable number.

2221121221 is a deficient number, since it is larger than the sum of its proper divisors (238085723).

2221121221 is a wasteful number, since it uses less digits than its factorization.

2221121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3013811.

The product of its digits is 64, while the sum is 16.

The square root of 2221121221 is about 47128.7727508366. The cubic root of 2221121221 is about 1304.7403310848.

Adding to 2221121221 its reverse (1221211222), we get a palindrome (3442332443).

Subtracting from 2221121221 its reverse (1221211222), we obtain a palindrome (999909999).

The spelling of 2221121221 in words is "two billion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty-one".