1311531138818 has 4 divisors (see below), whose sum is σ = 1967296708230. Its totient is φ = 655765569408.

The previous prime is 1311531138817. The next prime is 1311531138913. The reversal of 1311531138818 is 8188311351131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 910369781689 + 401161357129 = 954133^2 + 633373^2 .

It is a super-2 number, since 2×1311531138818² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1311531138817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327882784703 + ... + 327882784706.

Almost surely, 2^{1311531138818} is an apocalyptic number.

1311531138818 is a deficient number, since it is larger than the sum of its proper divisors (655765569412).

1311531138818 is an equidigital number, since it uses as much as digits as its factorization.

1311531138818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655765569411.

The product of its digits is 69120, while the sum is 44.

Adding to 1311531138818 its reverse (8188311351131), we get a palindrome (9499842489949).

The spelling of 1311531138818 in words is "one trillion, three hundred eleven billion, five hundred thirty-one million, one hundred thirty-eight thousand, eight hundred eighteen".