111660011581 has 2 divisors, whose sum is σ = 111660011582. Its totient is φ = 111660011580.

The previous prime is 111660011543. The next prime is 111660011591. The reversal of 111660011581 is 185110066111.

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., 71393168025 + 40266843556 = 267195^2 + 200666^2 .

It is a cyclic number.

It is not a de Polignac number, because 111660011581 - 2²⁵ = 111626457149 is a prime.

It is a super-2 number, since 2×111660011581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111660011591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55830005790 + 55830005791.

It is an arithmetic number, because the mean of its divisors is an integer number (55830005791).

Almost surely, 2^111660011581 is an apocalyptic number.

It is an amenable number.

111660011581 is a deficient number, since it is larger than the sum of its proper divisors (1).

111660011581 is an equidigital number, since it uses as much as digits as its factorization.

111660011581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 31.

Adding to 111660011581 its reverse (185110066111), we get a palindrome (296770077692).

The spelling of 111660011581 in words is "one hundred eleven billion, six hundred sixty million, eleven thousand, five hundred eighty-one".