81918182 has 16 divisors (see below), whose sum is σ = 129795072. Its totient is φ = 38714760.

The previous prime is 81918169. The next prime is 81918209. The reversal of 81918182 is 28181918.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12698 + ... + 18029.

It is an arithmetic number, because the mean of its divisors is an integer number (8112192).

Almost surely, 2^81918182 is an apocalyptic number.

81918182 is a deficient number, since it is larger than the sum of its proper divisors (47876890).

81918182 is a wasteful number, since it uses less digits than its factorization.

81918182 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30803.

The product of its digits is 9216, while the sum is 38.

The square root of 81918182 is about 9050.8663673706. The cubic root of 81918182 is about 434.3036058637.

The spelling of 81918182 in words is "eighty-one million, nine hundred eighteen thousand, one hundred eighty-two".