18156781219 has 2 divisors, whose sum is σ = 18156781220. Its totient is φ = 18156781218.

The previous prime is 18156781207. The next prime is 18156781271. The reversal of 18156781219 is 91218765181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18156781219 - 2⁷ = 18156781091 is a prime.

It is a super-2 number, since 2×18156781219² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18156781619) 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, 9078390609 + 9078390610.

It is an arithmetic number, because the mean of its divisors is an integer number (9078390610).

Almost surely, 2^18156781219 is an apocalyptic number.

18156781219 is a deficient number, since it is larger than the sum of its proper divisors (1).

18156781219 is an equidigital number, since it uses as much as digits as its factorization.

18156781219 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 49.

The spelling of 18156781219 in words is "eighteen billion, one hundred fifty-six million, seven hundred eighty-one thousand, two hundred nineteen".