81085307 has 4 divisors (see below), whose sum is σ = 81921336. Its totient is φ = 80249280.

The previous prime is 81085289. The next prime is 81085321. The reversal of 81085307 is 70358018.

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

It is a cyclic number.

It is not a de Polignac number, because 81085307 - 2¹⁸ = 80823163 is a prime.

It is a super-2 number, since 2×81085307² = 13149654022568498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81085507) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417869 + ... + 418062.

It is an arithmetic number, because the mean of its divisors is an integer number (20480334).

Almost surely, 2^81085307 is an apocalyptic number.

81085307 is a deficient number, since it is larger than the sum of its proper divisors (836029).

81085307 is an equidigital number, since it uses as much as digits as its factorization.

81085307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836028.

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 81085307 is about 9004.7380306148. The cubic root of 81085307 is about 432.8267116074.

The spelling of 81085307 in words is "eighty-one million, eighty-five thousand, three hundred seven".