81018 has 24 divisors (see below), whose sum is σ = 200928. Its totient is φ = 23112.

The previous prime is 81017. The next prime is 81019.

It is a happy number.

81018 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (81017) and next prime (81019).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an alternating number because its digits alternate between even and odd.

81018 is a strobogrammatic number because it is the same when read upside-down.

It is not an unprimeable number, because it can be changed into a prime (81013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 196 + ... + 447.

It is an arithmetic number, because the mean of its divisors is an integer number (8372).

2⁸¹⁰¹⁸ is an apocalyptic number.

81018 is an abundant number, since it is smaller than the sum of its proper divisors (119910).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100464).

81018 is a wasteful number, since it uses less digits than its factorization.

81018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658 (or 655 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 81018 is about 284.6366104351. The cubic root of 81018 is about 43.2706918709.

It can be divided in two parts, 810 and 18, that added together give a palindrome (828).

The spelling of 81018 in words is "eighty-one thousand, eighteen".