1221221111 has 8 divisors (see below), whose sum is σ = 1334581248. Its totient is φ = 1108251000.

The previous prime is 1221221093. The next prime is 1221221119. The reversal of 1221221111 is 1111221221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221221111 - 2¹⁰ = 1221220087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221119) 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 7 ways as a sum of consecutive naturals, for example, 90935 + ... + 103496.

It is an arithmetic number, because the mean of its divisors is an integer number (166822656).

Almost surely, 2^1221221111 is an apocalyptic number.

1221221111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221221111 is a deficient number, since it is larger than the sum of its proper divisors (113360137).

1221221111 is a wasteful number, since it uses less digits than its factorization.

1221221111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195013.

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

The square root of 1221221111 is about 34945.9741744310. The cubic root of 1221221111 is about 1068.8861122041.

Adding to 1221221111 its reverse (1111221221), we get a palindrome (2332442332).

It can be divided in two parts, 1221221 and 111, that multiplied together give a palindrome (135555531).

The spelling of 1221221111 in words is "one billion, two hundred twenty-one million, two hundred twenty-one thousand, one hundred eleven".