1211442121 has 4 divisors (see below), whose sum is σ = 1211525392. Its totient is φ = 1211358852.

The previous prime is 1211442097. The next prime is 1211442161. The reversal of 1211442121 is 1212441121.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1211442121 - 2¹¹ = 1211440073 is a prime.

It is a super-3 number, since 3×1211442121³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211442161) 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, 13455 + ... + 51028.

It is an arithmetic number, because the mean of its divisors is an integer number (302881348).

Almost surely, 2^1211442121 is an apocalyptic number.

It is an amenable number.

1211442121 is a deficient number, since it is larger than the sum of its proper divisors (83271).

1211442121 is an equidigital number, since it uses as much as digits as its factorization.

1211442121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83270.

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

The square root of 1211442121 is about 34805.7771210470. Note that the first 3 decimals coincide. The cubic root of 1211442121 is about 1066.0254095651.

Adding to 1211442121 its reverse (1212441121), we get a palindrome (2423883242).

The spelling of 1211442121 in words is "one billion, two hundred eleven million, four hundred forty-two thousand, one hundred twenty-one".