1211322121 has 4 divisors (see below), whose sum is σ = 1211891092. Its totient is φ = 1210753152.

The previous prime is 1211322107. The next prime is 1211322137. The reversal of 1211322121 is 1212231121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 249640000 + 961682121 = 15800^2 + 31011^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211322121 - 2¹⁵ = 1211289353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211322095 and 1211322104.

It is not an unprimeable number, because it can be changed into a prime (1211362121) 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, 281280 + ... + 285553.

It is an arithmetic number, because the mean of its divisors is an integer number (302972773).

Almost surely, 2^1211322121 is an apocalyptic number.

It is an amenable number.

1211322121 is a deficient number, since it is larger than the sum of its proper divisors (568971).

1211322121 is an equidigital number, since it uses as much as digits as its factorization.

1211322121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568970.

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

The square root of 1211322121 is about 34804.0532265999. The cubic root of 1211322121 is about 1065.9902098443.

Adding to 1211322121 its reverse (1212231121), we get a palindrome (2423553242).

The spelling of 1211322121 in words is "one billion, two hundred eleven million, three hundred twenty-two thousand, one hundred twenty-one".