11811213131 has 4 divisors (see below), whose sum is σ = 12505990392. Its totient is φ = 11116435872.

The previous prime is 11811213091. The next prime is 11811213137. The reversal of 11811213131 is 13131211811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13131211811 = 199 ⋅65985989.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11811213131 is a prime.

It is a super-2 number, since 2×11811213131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11811213097 and 11811213106.

It is not an unprimeable number, because it can be changed into a prime (11811213137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347388605 + ... + 347388638.

It is an arithmetic number, because the mean of its divisors is an integer number (3126497598).

Almost surely, 2^11811213131 is an apocalyptic number.

11811213131 is a deficient number, since it is larger than the sum of its proper divisors (694777261).

11811213131 is an equidigital number, since it uses as much as digits as its factorization.

11811213131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694777260.

The product of its digits is 144, while the sum is 23.

Adding to 11811213131 its reverse (13131211811), we get a palindrome (24942424942).

The spelling of 11811213131 in words is "eleven billion, eight hundred eleven million, two hundred thirteen thousand, one hundred thirty-one".