121111212221 has 4 divisors (see below), whose sum is σ = 121582462332. Its totient is φ = 120639962112.

The previous prime is 121111212197. The next prime is 121111212281. The reversal of 121111212221 is 122212111121.

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 79653772900 + 41457439321 = 282230^2 + 203611^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121111212221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121111212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121111212281) 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, 235624670 + ... + 235625183.

It is an arithmetic number, because the mean of its divisors is an integer number (30395615583).

Almost surely, 2^121111212221 is an apocalyptic number.

It is an amenable number.

121111212221 is a deficient number, since it is larger than the sum of its proper divisors (471250111).

121111212221 is an equidigital number, since it uses as much as digits as its factorization.

121111212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471250110.

The product of its digits is 32, while the sum is 17.

Adding to 121111212221 its reverse (122212111121), we get a palindrome (243323323342).

The spelling of 121111212221 in words is "one hundred twenty-one billion, one hundred eleven million, two hundred twelve thousand, two hundred twenty-one".