1212221111111 has 4 divisors (see below), whose sum is σ = 1283528235312. Its totient is φ = 1140913986912.

The previous prime is 1212221111099. The next prime is 1212221111117. The reversal of 1212221111111 is 1111111222121.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212221111111 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 71307124183 = 1212221111111 / (1 + 2 + 1 + 2 + 2 + 2 + 1 + 1 + 1 + 1 + 1 + 1 + 1).

It is a Duffinian number.

1212221111111 is a modest number, since divided by 1111111 gives 121222 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 1212221111111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212221111117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35653562075 + ... + 35653562108.

It is an arithmetic number, because the mean of its divisors is an integer number (320882058828).

Almost surely, 2^{1212221111111} is an apocalyptic number.

1212221111111 is a deficient number, since it is larger than the sum of its proper divisors (71307124201).

1212221111111 is an equidigital number, since it uses as much as digits as its factorization.

1212221111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71307124200.

The product of its digits is 16, while the sum is 17.

Adding to 1212221111111 its reverse (1111111222121), we get a palindrome (2323332333232).

The spelling of 1212221111111 in words is "one trillion, two hundred twelve billion, two hundred twenty-one million, one hundred eleven thousand, one hundred eleven".