81718182 has 72 divisors (see below), whose sum is σ = 221837616. Its totient is φ = 21549024.

The previous prime is 81718177. The next prime is 81718187. The reversal of 81718182 is 28181718.

It is an interprime number because it is at equal distance from previous prime (81718177) and next prime (81718187).

It is a super-2 number, since 2×81718182² = 13355722538770248, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81718187) 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 35 ways as a sum of consecutive naturals, for example, 7903 + ... + 15029.

It is an arithmetic number, because the mean of its divisors is an integer number (3081078).

Almost surely, 2^81718182 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81718182, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110918808).

81718182 is an abundant number, since it is smaller than the sum of its proper divisors (140119434).

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

81718182 is a wasteful number, since it uses less digits than its factorization.

81718182 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7162 (or 7152 counting only the distinct ones).

The product of its digits is 7168, while the sum is 36.

The square root of 81718182 is about 9039.8109493507. The cubic root of 81718182 is about 433.9498728092.

The spelling of 81718182 in words is "eighty-one million, seven hundred eighteen thousand, one hundred eighty-two".