2111312121221 has 4 divisors (see below), whose sum is σ = 2184115987500. Its totient is φ = 2038508254944.

The previous prime is 2111312121143. The next prime is 2111312121223. The reversal of 2111312121221 is 1221212131112.

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 920352422500 + 1190959698721 = 959350^2 + 1091311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2111312121221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2111312121193 and 2111312121202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2111312121223) 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, 36401933096 + ... + 36401933153.

It is an arithmetic number, because the mean of its divisors is an integer number (546028996875).

Almost surely, 2^{2111312121221} is an apocalyptic number.

It is an amenable number.

2111312121221 is a deficient number, since it is larger than the sum of its proper divisors (72803866279).

2111312121221 is an equidigital number, since it uses as much as digits as its factorization.

2111312121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72803866278.

The product of its digits is 96, while the sum is 20.

Adding to 2111312121221 its reverse (1221212131112), we get a palindrome (3332524252333).

The spelling of 2111312121221 in words is "two trillion, one hundred eleven billion, three hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".