81085306 has 4 divisors (see below), whose sum is σ = 121627962. Its totient is φ = 40542652.

The previous prime is 81085289. The next prime is 81085321. The reversal of 81085306 is 60358018.

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

It can be written as a sum of positive squares in only one way, i.e., 62552281 + 18533025 = 7909^2 + 4305^2 .

It is a super-2 number, since 2×81085306² = 13149653698227272, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20271325 + ... + 20271328.

Almost surely, 2^81085306 is an apocalyptic number.

81085306 is a deficient number, since it is larger than the sum of its proper divisors (40542656).

81085306 is a wasteful number, since it uses less digits than its factorization.

81085306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40542655.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 81085306 is about 9004.7379750884. The cubic root of 81085306 is about 432.8267098281.

The spelling of 81085306 in words is "eighty-one million, eighty-five thousand, three hundred six".