81944786 has 32 divisors (see below), whose sum is σ = 153740160. Its totient is φ = 31824000.

The previous prime is 81944771. The next prime is 81944789. The reversal of 81944786 is 68744918.

It is a self number, because there is not a number n which added to its sum of digits gives 81944786.

It is not an unprimeable number, because it can be changed into a prime (81944789) 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 15 ways as a sum of consecutive naturals, for example, 62336 + ... + 63636.

It is an arithmetic number, because the mean of its divisors is an integer number (4804380).

Almost surely, 2^81944786 is an apocalyptic number.

81944786 is a deficient number, since it is larger than the sum of its proper divisors (71795374).

81944786 is a wasteful number, since it uses less digits than its factorization.

81944786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1730.

The product of its digits is 387072, while the sum is 47.

The square root of 81944786 is about 9052.3359416230. The cubic root of 81944786 is about 434.3506160320.

The spelling of 81944786 in words is "eighty-one million, nine hundred forty-four thousand, seven hundred eighty-six".