1221122111 has 16 divisors (see below), whose sum is σ = 1385748000. Its totient is φ = 1065859200.

The previous prime is 1221122099. The next prime is 1221122159. The reversal of 1221122111 is 1112211221.

It is a cyclic number.

It is not a de Polignac number, because 1221122111 - 2¹⁴ = 1221105727 is a prime.

It is a super-2 number, since 2×1221122111² = 2982278419946192642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221152111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47165 + ... + 68313.

It is an arithmetic number, because the mean of its divisors is an integer number (86609250).

Almost surely, 2^1221122111 is an apocalyptic number.

1221122111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221122111 is a deficient number, since it is larger than the sum of its proper divisors (164625889).

1221122111 is a wasteful number, since it uses less digits than its factorization.

1221122111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21370.

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

The square root of 1221122111 is about 34944.5576735491. The cubic root of 1221122111 is about 1068.8572278402.

Adding to 1221122111 its reverse (1112211221), we get a palindrome (2333333332).

It can be divided in two parts, 12211221 and 11, that multiplied together give a palindrome (134323431).

The spelling of 1221122111 in words is "one billion, two hundred twenty-one million, one hundred twenty-two thousand, one hundred eleven".