2156122221 has 16 divisors (see below), whose sum is σ = 3142748160. Its totient is φ = 1304003120.

The previous prime is 2156122219. The next prime is 2156122229. The reversal of 2156122221 is 1222216512.

It is a cyclic number.

It is not a de Polignac number, because 2156122221 - 2¹ = 2156122219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2156122191 and 2156122200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156122229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52395 + ... + 84008.

It is an arithmetic number, because the mean of its divisors is an integer number (196421760).

Almost surely, 2^2156122221 is an apocalyptic number.

It is an amenable number.

2156122221 is a deficient number, since it is larger than the sum of its proper divisors (986625939).

2156122221 is a wasteful number, since it uses less digits than its factorization.

2156122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136896.

The product of its digits is 960, while the sum is 24.

The square root of 2156122221 is about 46434.0631541113. The cubic root of 2156122221 is about 1291.8867930871.

Adding to 2156122221 its reverse (1222216512), we get a palindrome (3378338733).

The spelling of 2156122221 in words is "two billion, one hundred fifty-six million, one hundred twenty-two thousand, two hundred twenty-one".