1221232111 has 32 divisors (see below), whose sum is σ = 1442587968. Its totient is φ = 1021501440.

The previous prime is 1221232099. The next prime is 1221232123. The reversal of 1221232111 is 1112321221.

It is an interprime number because it is at equal distance from previous prime (1221232099) and next prime (1221232123).

It is not a de Polignac number, because 1221232111 - 2⁷ = 1221231983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221232151) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1869861 + ... + 1870513.

It is an arithmetic number, because the mean of its divisors is an integer number (45080874).

Almost surely, 2^1221232111 is an apocalyptic number.

1221232111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221232111 is a deficient number, since it is larger than the sum of its proper divisors (221355857).

1221232111 is a wasteful number, since it uses less digits than its factorization.

1221232111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891.

The product of its digits is 48, while the sum is 16.

The square root of 1221232111 is about 34946.1315598737. The cubic root of 1221232111 is about 1068.8893214815.

Adding to 1221232111 its reverse (1112321221), we get a palindrome (2333553332).

It can be divided in two parts, 1221 and 232111, that added together give a palindrome (233332).

The spelling of 1221232111 in words is "one billion, two hundred twenty-one million, two hundred thirty-two thousand, one hundred eleven".