81071217018 has 36 divisors (see below), whose sum is σ = 193074570234. Its totient is φ = 24567034800.

The previous prime is 81071217013. The next prime is 81071217067.

81071217018 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 45178777809 + 35892439209 = 212553^2 + 189453^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81071217013) 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 in 17 ways as a sum of consecutive naturals, for example, 18609213 + ... + 18613568.

Almost surely, 2^81071217018 is an apocalyptic number.

81071217018 is an abundant number, since it is smaller than the sum of its proper divisors (112003353216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81071217018 is a wasteful number, since it uses less digits than its factorization.

81071217018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37222811 (or 37222797 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 36.

The spelling of 81071217018 in words is "eighty-one billion, seventy-one million, two hundred seventeen thousand, eighteen".