2021121111 has 4 divisors (see below), whose sum is σ = 2694828152. Its totient is φ = 1347414072.

The previous prime is 2021121107. The next prime is 2021121139. The reversal of 2021121111 is 1111211202.

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

It is not a de Polignac number, because 2021121111 - 2² = 2021121107 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 (2021121191) 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, 336853516 + ... + 336853521.

It is an arithmetic number, because the mean of its divisors is an integer number (673707038).

Almost surely, 2^2021121111 is an apocalyptic number.

2021121111 is a deficient number, since it is larger than the sum of its proper divisors (673707041).

2021121111 is an equidigital number, since it uses as much as digits as its factorization.

2021121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673707040.

The product of its (nonzero) digits is 8, while the sum is 12.

The square root of 2021121111 is about 44956.8805746128. The cubic root of 2021121111 is about 1264.3406836763.

Adding to 2021121111 its reverse (1111211202), we get a palindrome (3132332313).

Subtracting from 2021121111 its reverse (1111211202), we obtain a palindrome (909909909).

The spelling of 2021121111 in words is "two billion, twenty-one million, one hundred twenty-one thousand, one hundred eleven".