81845305 has 4 divisors (see below), whose sum is σ = 98214372. Its totient is φ = 65476240.

The previous prime is 81845299. The next prime is 81845329. The reversal of 81845305 is 50354818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50354818 = 2 ⋅25177409.

It can be written as a sum of positive squares in 2 ways, for example, as 8982009 + 72863296 = 2997^2 + 8536^2 .

It is not a de Polignac number, because 81845305 - 2⁵ = 81845273 is a prime.

It is a Duffinian 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 3 ways as a sum of consecutive naturals, for example, 8184526 + ... + 8184535.

It is an arithmetic number, because the mean of its divisors is an integer number (24553593).

Almost surely, 2^81845305 is an apocalyptic number.

It is an amenable number.

81845305 is a deficient number, since it is larger than the sum of its proper divisors (16369067).

81845305 is a wasteful number, since it uses less digits than its factorization.

81845305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16369066.

The product of its (nonzero) digits is 19200, while the sum is 34.

The square root of 81845305 is about 9046.8395033846. The cubic root of 81845305 is about 434.1747775882.

The spelling of 81845305 in words is "eighty-one million, eight hundred forty-five thousand, three hundred five".