1221424111 has 4 divisors (see below), whose sum is σ = 1226176992. Its totient is φ = 1216671232.

The previous prime is 1221424091. The next prime is 1221424133. The reversal of 1221424111 is 1114241221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1114241221 = 149 ⋅7478129.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221424111 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 (1221425111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2376055 + ... + 2376568.

It is an arithmetic number, because the mean of its divisors is an integer number (306544248).

Almost surely, 2^1221424111 is an apocalyptic number.

1221424111 is a deficient number, since it is larger than the sum of its proper divisors (4752881).

1221424111 is an equidigital number, since it uses as much as digits as its factorization.

1221424111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4752880.

The product of its digits is 128, while the sum is 19.

The square root of 1221424111 is about 34948.8785370861. The cubic root of 1221424111 is about 1068.9453348562.

Adding to 1221424111 its reverse (1114241221), we get a palindrome (2335665332).

It can be divided in two parts, 122142 and 4111, that added together give a triangular number (126253 = T₅₀₂).

The spelling of 1221424111 in words is "one billion, two hundred twenty-one million, four hundred twenty-four thousand, one hundred eleven".