81005307 has 8 divisors (see below), whose sum is σ = 108133200. Its totient is φ = 53940480.

The previous prime is 81005279. The next prime is 81005311. The reversal of 81005307 is 70350018.

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

It is not a de Polignac number, because 81005307 - 2⁷ = 81005179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81007307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12682 + ... + 17967.

It is an arithmetic number, because the mean of its divisors is an integer number (13516650).

Almost surely, 2^81005307 is an apocalyptic number.

81005307 is a deficient number, since it is larger than the sum of its proper divisors (27127893).

81005307 is a wasteful number, since it uses less digits than its factorization.

81005307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31533.

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 81005307 is about 9000.2948285042. The cubic root of 81005307 is about 432.6843202914.

The spelling of 81005307 in words is "eighty-one million, five thousand, three hundred seven".