111212122221 has 48 divisors (see below), whose sum is σ = 168626465280. Its totient is φ = 70561065600.

The previous prime is 111212122199. The next prime is 111212122247. The reversal of 111212122221 is 122221212111.

111212122221 is a `hidden beast` number, since 111 + 212 + 122 + 221 = 666.

It is not a de Polignac number, because 111212122221 - 2¹³ = 111212114029 is a prime.

It is a super-2 number, since 2×111212122221² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 111212122194 and 111212122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111212122321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2771620 + ... + 2811458.

It is an arithmetic number, because the mean of its divisors is an integer number (3513051360).

Almost surely, 2^111212122221 is an apocalyptic number.

It is an amenable number.

111212122221 is a deficient number, since it is larger than the sum of its proper divisors (57414343059).

111212122221 is a wasteful number, since it uses less digits than its factorization.

111212122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40066 (or 40063 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 111212122221 its reverse (122221212111), we get a palindrome (233433334332).

The spelling of 111212122221 in words is "one hundred eleven billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-one".