1810121121211 has 4 divisors (see below), whose sum is σ = 1949361207472. Its totient is φ = 1670881034952.

The previous prime is 1810121121197. The next prime is 1810121121217. The reversal of 1810121121211 is 1121211210181.

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 1810121121211 - 2⁹ = 1810121120699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1810121121217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69620043111 + ... + 69620043136.

It is an arithmetic number, because the mean of its divisors is an integer number (487340301868).

Almost surely, 2^{1810121121211} is an apocalyptic number.

1810121121211 is a deficient number, since it is larger than the sum of its proper divisors (139240086261).

1810121121211 is a wasteful number, since it uses less digits than its factorization.

1810121121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139240086260.

The product of its (nonzero) digits is 64, while the sum is 22.

Adding to 1810121121211 its reverse (1121211210181), we get a palindrome (2931332331392).

The spelling of 1810121121211 in words is "one trillion, eight hundred ten billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred eleven".