81085305 has 64 divisors (see below), whose sum is σ = 158515200. Its totient is φ = 34594560.

The previous prime is 81085289. The next prime is 81085321. The reversal of 81085305 is 50358018.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81085289) and next prime (81085321).

It is not a de Polignac number, because 81085305 - 2⁴ = 81085289 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 93966 + ... + 94824.

It is an arithmetic number, because the mean of its divisors is an integer number (2476800).

Almost surely, 2^81085305 is an apocalyptic number.

It is an amenable number.

81085305 is a deficient number, since it is larger than the sum of its proper divisors (77429895).

81085305 is a wasteful number, since it uses less digits than its factorization.

81085305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 934.

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 81085305 is about 9004.7379195621. The cubic root of 81085305 is about 432.8267080488.

The spelling of 81085305 in words is "eighty-one million, eighty-five thousand, three hundred five".