81085211 has 2 divisors, whose sum is σ = 81085212. Its totient is φ = 81085210.

The previous prime is 81085187. The next prime is 81085219. The reversal of 81085211 is 11258018.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81085211 is a prime.

It is a super-2 number, since 2×81085211² = 13149622885829042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81085219) by changing a digit.

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 as a sum of consecutive naturals, namely, 40542605 + 40542606.

It is an arithmetic number, because the mean of its divisors is an integer number (40542606).

Almost surely, 2^81085211 is an apocalyptic number.

81085211 is a deficient number, since it is larger than the sum of its proper divisors (1).

81085211 is an equidigital number, since it uses as much as digits as its factorization.

81085211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 81085211 is about 9004.7327000861. The cubic root of 81085211 is about 432.8265407940.

The spelling of 81085211 in words is "eighty-one million, eighty-five thousand, two hundred eleven".