1311343021 has 4 divisors (see below), whose sum is σ = 1311772000. Its totient is φ = 1310914044.

The previous prime is 1311342983. The next prime is 1311343031. The reversal of 1311343021 is 1203431131.

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.

It is a cyclic number.

It is not a de Polignac number, because 1311343021 - 2⁹ = 1311342509 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1311343021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311343031) 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, 209871 + ... + 216028.

It is an arithmetic number, because the mean of its divisors is an integer number (327943000).

Almost surely, 2^1311343021 is an apocalyptic number.

It is an amenable number.

1311343021 is a deficient number, since it is larger than the sum of its proper divisors (428979).

1311343021 is an equidigital number, since it uses as much as digits as its factorization.

1311343021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428978.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 1311343021 is about 36212.4705177650. The cubic root of 1311343021 is about 1094.5579753672.

Adding to 1311343021 its reverse (1203431131), we get a palindrome (2514774152).

The spelling of 1311343021 in words is "one billion, three hundred eleven million, three hundred forty-three thousand, twenty-one".