111121211222221 has 4 divisors (see below), whose sum is σ = 111122305779744. Its totient is φ = 111120116664700.

The previous prime is 111121211222179. The next prime is 111121211222267. The reversal of 111121211222221 is 122222112121111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111121211222221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 111121211222192 and 111121211222201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111121211222521) 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, 547126465 + ... + 547329526.

It is an arithmetic number, because the mean of its divisors is an integer number (27780576444936).

Almost surely, 2^{111121211222221} is an apocalyptic number.

It is an amenable number.

111121211222221 is a deficient number, since it is larger than the sum of its proper divisors (1094557523).

111121211222221 is a wasteful number, since it uses less digits than its factorization.

111121211222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1094557522.

The product of its digits is 128, while the sum is 22.

Adding to 111121211222221 its reverse (122222112121111), we get a palindrome (233343323343332).

The spelling of 111121211222221 in words is "one hundred eleven trillion, one hundred twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred twenty-one".