81986845 has 8 divisors (see below), whose sum is σ = 98468280. Its totient is φ = 65533440.

The previous prime is 81986791. The next prime is 81986893. The reversal of 81986845 is 54868918.

It can be written as a sum of positive squares in 4 ways, for example, as 34363044 + 47623801 = 5862^2 + 6901^2 .

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

It is not a de Polignac number, because 81986845 - 2¹³ = 81978653 is a prime.

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, 85 + ... + 12805.

It is an arithmetic number, because the mean of its divisors is an integer number (12308535).

Almost surely, 2^81986845 is an apocalyptic number.

It is an amenable number.

81986845 is a deficient number, since it is larger than the sum of its proper divisors (16481435).

81986845 is a wasteful number, since it uses less digits than its factorization.

81986845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14015.

The product of its digits is 552960, while the sum is 49.

The square root of 81986845 is about 9054.6587456403. The cubic root of 81986845 is about 434.4249149547.

The spelling of 81986845 in words is "eighty-one million, nine hundred eighty-six thousand, eight hundred forty-five".