1158168191581 has 2 divisors, whose sum is σ = 1158168191582. Its totient is φ = 1158168191580.

The previous prime is 1158168191563. The next prime is 1158168191623. The reversal of 1158168191581 is 1851918618511.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1125171469081 + 32996722500 = 1060741^2 + 181650^2 .

It is a cyclic number.

It is not a de Polignac number, because 1158168191581 - 2²¹ = 1158166094429 is a prime.

It is a super-2 number, since 2×1158168191581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1158168191501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 579084095790 + 579084095791.

It is an arithmetic number, because the mean of its divisors is an integer number (579084095791).

Almost surely, 2^{1158168191581} is an apocalyptic number.

It is an amenable number.

1158168191581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1158168191581 is an equidigital number, since it uses as much as digits as its factorization.

1158168191581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 691200, while the sum is 55.

The spelling of 1158168191581 in words is "one trillion, one hundred fifty-eight billion, one hundred sixty-eight million, one hundred ninety-one thousand, five hundred eighty-one".