81866894 has 8 divisors (see below), whose sum is σ = 122839248. Its totient is φ = 40920480.

The previous prime is 81866893. The next prime is 81866899. The reversal of 81866894 is 49866818.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81866891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7094 + ... + 14630.

It is an arithmetic number, because the mean of its divisors is an integer number (15354906).

Almost surely, 2^81866894 is an apocalyptic number.

81866894 is a deficient number, since it is larger than the sum of its proper divisors (40972354).

81866894 is a wasteful number, since it uses less digits than its factorization.

81866894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12970.

The product of its digits is 663552, while the sum is 50.

The square root of 81866894 is about 9048.0326038316. The cubic root of 81866894 is about 434.2129494997.

The spelling of 81866894 in words is "eighty-one million, eight hundred sixty-six thousand, eight hundred ninety-four".