11891395181 has 2 divisors, whose sum is σ = 11891395182. Its totient is φ = 11891395180.

The previous prime is 11891395151. The next prime is 11891395193. The reversal of 11891395181 is 18159319811.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6064515625 + 5826879556 = 77875^2 + 76334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11891395181 is a prime.

It is a super-2 number, since 2×11891395181² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11891395141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5945697590 + 5945697591.

It is an arithmetic number, because the mean of its divisors is an integer number (5945697591).

Almost surely, 2^11891395181 is an apocalyptic number.

It is an amenable number.

11891395181 is a deficient number, since it is larger than the sum of its proper divisors (1).

11891395181 is an equidigital number, since it uses as much as digits as its factorization.

11891395181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 47.

The spelling of 11891395181 in words is "eleven billion, eight hundred ninety-one million, three hundred ninety-five thousand, one hundred eighty-one".