121221121221111 has 4 divisors (see below), whose sum is σ = 161628161628152. Its totient is φ = 80814080814072.

The previous prime is 121221121221049. The next prime is 121221121221121. The reversal of 121221121221111 is 111122121122121.

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

It is a de Polignac number, because none of the positive numbers 2^k-121221121221111 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 (121221121221121) 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, 20203520203516 + ... + 20203520203521.

It is an arithmetic number, because the mean of its divisors is an integer number (40407040407038).

Almost surely, 2^{121221121221111} is an apocalyptic number.

121221121221111 is a deficient number, since it is larger than the sum of its proper divisors (40407040407041).

121221121221111 is an equidigital number, since it uses as much as digits as its factorization.

121221121221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40407040407040.

The product of its digits is 64, while the sum is 21.

Adding to 121221121221111 its reverse (111122121122121), we get a palindrome (232343242343232).

The spelling of 121221121221111 in words is "one hundred twenty-one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred eleven".