2121311111 has 4 divisors (see below), whose sum is σ = 2194459800. Its totient is φ = 2048162424.

The previous prime is 2121311089. The next prime is 2121311147. The reversal of 2121311111 is 1111131212.

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

It is a cyclic number.

It is not a de Polignac number, because 2121311111 - 2¹⁸ = 2121048967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121311011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36574301 + ... + 36574358.

It is an arithmetic number, because the mean of its divisors is an integer number (548614950).

Almost surely, 2^2121311111 is an apocalyptic number.

2121311111 is a deficient number, since it is larger than the sum of its proper divisors (73148689).

2121311111 is an equidigital number, since it uses as much as digits as its factorization.

2121311111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73148688.

The product of its digits is 12, while the sum is 14.

The square root of 2121311111 is about 46057.6932878754. The cubic root of 2121311111 is about 1284.8964293477.

Adding to 2121311111 its reverse (1111131212), we get a palindrome (3232442323).

The spelling of 2121311111 in words is "two billion, one hundred twenty-one million, three hundred eleven thousand, one hundred eleven".