81105305 has 4 divisors (see below), whose sum is σ = 97326372. Its totient is φ = 64884240.

The previous prime is 81105293. The next prime is 81105307. The reversal of 81105305 is 50350118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 48706441 + 32398864 = 6979^2 + 5692^2 .

It is not a de Polignac number, because 81105305 - 2²⁰ = 80056729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81105307) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 8110526 + ... + 8110535.

It is an arithmetic number, because the mean of its divisors is an integer number (24331593).

Almost surely, 2^81105305 is an apocalyptic number.

It is an amenable number.

81105305 is a deficient number, since it is larger than the sum of its proper divisors (16221067).

81105305 is a wasteful number, since it uses less digits than its factorization.

81105305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16221066.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 81105305 is about 9005.8483775822. The cubic root of 81105305 is about 432.8622912433.

The spelling of 81105305 in words is "eighty-one million, one hundred five thousand, three hundred five".