1211131121 has 4 divisors (see below), whose sum is σ = 1211541744. Its totient is φ = 1210720500.

The previous prime is 1211131111. The next prime is 1211131123. The reversal of 1211131121 is 1211311121.

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.

It is a cyclic number.

It is not a de Polignac number, because 1211131121 - 2⁶ = 1211131057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211131096 and 1211131105.

It is not an unprimeable number, because it can be changed into a prime (1211131123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200855 + ... + 206796.

It is an arithmetic number, because the mean of its divisors is an integer number (302885436).

Almost surely, 2^1211131121 is an apocalyptic number.

It is an amenable number.

1211131121 is a deficient number, since it is larger than the sum of its proper divisors (410623).

1211131121 is an equidigital number, since it uses as much as digits as its factorization.

1211131121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410622.

The product of its digits is 12, while the sum is 14.

The square root of 1211131121 is about 34801.3091851442. The cubic root of 1211131121 is about 1065.9341788269.

Adding to 1211131121 its reverse (1211311121), we get a palindrome (2422442242).

The spelling of 1211131121 in words is "one billion, two hundred eleven million, one hundred thirty-one thousand, one hundred twenty-one".