81994845 has 16 divisors (see below), whose sum is σ = 135424512. Its totient is φ = 42319680.

The previous prime is 81994817. The next prime is 81994867. The reversal of 81994845 is 54849918.

It is not a de Polignac number, because 81994845 - 2⁵ = 81994813 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81994794 and 81994803.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87702 + ... + 88631.

It is an arithmetic number, because the mean of its divisors is an integer number (8464032).

Almost surely, 2^81994845 is an apocalyptic number.

It is an amenable number.

81994845 is a deficient number, since it is larger than the sum of its proper divisors (53429667).

81994845 is a wasteful number, since it uses less digits than its factorization.

81994845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176372.

The product of its digits is 414720, while the sum is 48.

The square root of 81994845 is about 9055.1004964053. The cubic root of 81994845 is about 434.4390444015.

The spelling of 81994845 in words is "eighty-one million, nine hundred ninety-four thousand, eight hundred forty-five".