1311213121121 has 4 divisors (see below), whose sum is σ = 1329174944772. Its totient is φ = 1293251297472.

The previous prime is 1311213121117. The next prime is 1311213121129. The reversal of 1311213121121 is 1211213121131.

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 514547982400 + 796665138721 = 717320^2 + 892561^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311213121121 - 2² = 1311213121117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1311213121093 and 1311213121102.

It is not an unprimeable number, because it can be changed into a prime (1311213121129) 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, 8980911716 + ... + 8980911861.

It is an arithmetic number, because the mean of its divisors is an integer number (332293736193).

Almost surely, 2^{1311213121121} is an apocalyptic number.

It is an amenable number.

1311213121121 is a deficient number, since it is larger than the sum of its proper divisors (17961823651).

1311213121121 is an equidigital number, since it uses as much as digits as its factorization.

1311213121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17961823650.

The product of its digits is 72, while the sum is 20.

Adding to 1311213121121 its reverse (1211213121131), we get a palindrome (2522426242252).

The spelling of 1311213121121 in words is "one trillion, three hundred eleven billion, two hundred thirteen million, one hundred twenty-one thousand, one hundred twenty-one".