18365181881 has 2 divisors, whose sum is σ = 18365181882. Its totient is φ = 18365181880.

The previous prime is 18365181847. The next prime is 18365181941. The reversal of 18365181881 is 18818156381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17977446400 + 387735481 = 134080^2 + 19691^2 .

It is a cyclic number.

It is not a de Polignac number, because 18365181881 - 2⁶ = 18365181817 is a prime.

It is a super-2 number, since 2×18365181881² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18365181811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9182590940 + 9182590941.

It is an arithmetic number, because the mean of its divisors is an integer number (9182590941).

Almost surely, 2^18365181881 is an apocalyptic number.

It is an amenable number.

18365181881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18365181881 is an equidigital number, since it uses as much as digits as its factorization.

18365181881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 368640, while the sum is 50.

The spelling of 18365181881 in words is "eighteen billion, three hundred sixty-five million, one hundred eighty-one thousand, eight hundred eighty-one".