2131011221 has 4 divisors (see below), whose sum is σ = 2152110444. Its totient is φ = 2109912000.

The previous prime is 2131011167. The next prime is 2131011229. The reversal of 2131011221 is 1221101312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1733806321 + 397204900 = 41639^2 + 19930^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2131011221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2131011196 and 2131011205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131011229) 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, 10549460 + ... + 10549661.

It is an arithmetic number, because the mean of its divisors is an integer number (538027611).

Almost surely, 2^2131011221 is an apocalyptic number.

It is an amenable number.

2131011221 is a deficient number, since it is larger than the sum of its proper divisors (21099223).

2131011221 is a wasteful number, since it uses less digits than its factorization.

2131011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21099222.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 2131011221 is about 46162.8770875473. The cubic root of 2131011221 is about 1286.8519318167.

Adding to 2131011221 its reverse (1221101312), we get a palindrome (3352112533).

Subtracting from 2131011221 its reverse (1221101312), we obtain a palindrome (909909909).

The spelling of 2131011221 in words is "two billion, one hundred thirty-one million, eleven thousand, two hundred twenty-one".