1221112121 has 4 divisors (see below), whose sum is σ = 1285381200. Its totient is φ = 1156843044.

The previous prime is 1221112117. The next prime is 1221112133. The reversal of 1221112121 is 1212111221.

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 not a de Polignac number, because 1221112121 - 2² = 1221112117 is a prime.

It is a super-2 number, since 2×1221112121² = 2982229624106237282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221112096 and 1221112105.

It is not an unprimeable number, because it can be changed into a prime (1221112171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32134511 + ... + 32134548.

It is an arithmetic number, because the mean of its divisors is an integer number (321345300).

Almost surely, 2^1221112121 is an apocalyptic number.

It is an amenable number.

1221112121 is a deficient number, since it is larger than the sum of its proper divisors (64269079).

1221112121 is an equidigital number, since it uses as much as digits as its factorization.

1221112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64269078.

The product of its digits is 16, while the sum is 14.

The square root of 1221112121 is about 34944.4147325435. The cubic root of 1221112121 is about 1068.8543130586.

Adding to 1221112121 its reverse (1212111221), we get a palindrome (2433223342).

The spelling of 1221112121 in words is "one billion, two hundred twenty-one million, one hundred twelve thousand, one hundred twenty-one".