1312331100221 has 4 divisors (see below), whose sum is σ = 1312337154492. Its totient is φ = 1312325045952.

The previous prime is 1312331100191. The next prime is 1312331100257. The reversal of 1312331100221 is 1220011332131.

It is a happy number.

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 7056840025 + 1305274260196 = 84005^2 + 1142486^2 .

It is a cyclic number.

It is not a de Polignac number, because 1312331100221 - 2³⁸ = 1037453193277 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 = 1312331100193 and 1312331100202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312331100281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2689436 + ... + 3139701.

It is an arithmetic number, because the mean of its divisors is an integer number (328084288623).

Almost surely, 2^{1312331100221} is an apocalyptic number.

It is an amenable number.

1312331100221 is a deficient number, since it is larger than the sum of its proper divisors (6054271).

1312331100221 is an equidigital number, since it uses as much as digits as its factorization.

1312331100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6054270.

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 1312331100221 its reverse (1220011332131), we get a palindrome (2532342432352).

The spelling of 1312331100221 in words is "one trillion, three hundred twelve billion, three hundred thirty-one million, one hundred thousand, two hundred twenty-one".