2131122221 has 4 divisors (see below), whose sum is σ = 2151812832. Its totient is φ = 2110431612.

The previous prime is 2131122199. The next prime is 2131122223. The reversal of 2131122221 is 1222211312.

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 2131122221 - 2⁶ = 2131122157 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 2131122221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131122223) 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, 10345151 + ... + 10345356.

It is an arithmetic number, because the mean of its divisors is an integer number (537953208).

Almost surely, 2^2131122221 is an apocalyptic number.

It is an amenable number.

2131122221 is a deficient number, since it is larger than the sum of its proper divisors (20690611).

2131122221 is a wasteful number, since it uses less digits than its factorization.

2131122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20690610.

The product of its digits is 96, while the sum is 17.

The square root of 2131122221 is about 46164.0793366444. The cubic root of 2131122221 is about 1286.8742745873.

Adding to 2131122221 its reverse (1222211312), we get a palindrome (3353333533).

The spelling of 2131122221 in words is "two billion, one hundred thirty-one million, one hundred twenty-two thousand, two hundred twenty-one".