1211311321 has 4 divisors (see below), whose sum is σ = 1321430544. Its totient is φ = 1101192100.

The previous prime is 1211311289. The next prime is 1211311327. The reversal of 1211311321 is 1231131121.

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 an emirpimes, since its reverse is a distinct semiprime: 1231131121 = 11 ⋅111921011.

It is a cyclic number.

It is not a de Polignac number, because 1211311321 - 2⁵ = 1211311289 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211311295 and 1211311304.

It is not an unprimeable number, because it can be changed into a prime (1211311327) 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, 55059595 + ... + 55059616.

It is an arithmetic number, because the mean of its divisors is an integer number (330357636).

Almost surely, 2^1211311321 is an apocalyptic number.

1211311321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211311321 is a deficient number, since it is larger than the sum of its proper divisors (110119223).

1211311321 is a wasteful number, since it uses less digits than its factorization.

1211311321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110119222.

The product of its digits is 36, while the sum is 16.

The square root of 1211311321 is about 34803.8980719114. The cubic root of 1211311321 is about 1065.9870417554.

Adding to 1211311321 its reverse (1231131121), we get a palindrome (2442442442).

The spelling of 1211311321 in words is "one billion, two hundred eleven million, three hundred eleven thousand, three hundred twenty-one".