1311323021 has 4 divisors (see below), whose sum is σ = 1312019100. Its totient is φ = 1310626944.

The previous prime is 1311323009. The next prime is 1311323051. The reversal of 1311323021 is 1203231131.

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 386554921 + 924768100 = 19661^2 + 30410^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311323021 - 2¹⁰ = 1311321997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311323051) 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, 345206 + ... + 348983.

It is an arithmetic number, because the mean of its divisors is an integer number (328004775).

Almost surely, 2^1311323021 is an apocalyptic number.

It is an amenable number.

1311323021 is a deficient number, since it is larger than the sum of its proper divisors (696079).

1311323021 is an equidigital number, since it uses as much as digits as its factorization.

1311323021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 696078.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1311323021 is about 36212.1943687482. The cubic root of 1311323021 is about 1094.5524107742.

Adding to 1311323021 its reverse (1203231131), we get a palindrome (2514554152).

The spelling of 1311323021 in words is "one billion, three hundred eleven million, three hundred twenty-three thousand, twenty-one".