18271817281 has 2 divisors, whose sum is σ = 18271817282. Its totient is φ = 18271817280.

The previous prime is 18271817261. The next prime is 18271817287.

It is a happy number.

18271817281 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16075957681 + 2195859600 = 126791^2 + 46860^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 18271817281 - 2¹³ = 18271809089 is a prime.

It is a super-2 number, since 2×18271817281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18271817287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9135908640 + 9135908641.

It is an arithmetic number, because the mean of its divisors is an integer number (9135908641).

Almost surely, 2^18271817281 is an apocalyptic number.

It is an amenable number.

18271817281 is a deficient number, since it is larger than the sum of its proper divisors (1).

18271817281 is an equidigital number, since it uses as much as digits as its factorization.

18271817281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100352, while the sum is 46.

The spelling of 18271817281 in words is "eighteen billion, two hundred seventy-one million, eight hundred seventeen thousand, two hundred eighty-one".