81085187 has 2 divisors, whose sum is σ = 81085188. Its totient is φ = 81085186.

The previous prime is 81085183. The next prime is 81085211. The reversal of 81085187 is 78158018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81085187 - 2² = 81085183 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81085187.

It is not a weakly prime, because it can be changed into another prime (81085183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40542593 + 40542594.

It is an arithmetic number, because the mean of its divisors is an integer number (40542594).

Almost surely, 2^81085187 is an apocalyptic number.

81085187 is a deficient number, since it is larger than the sum of its proper divisors (1).

81085187 is an equidigital number, since it uses as much as digits as its factorization.

81085187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17920, while the sum is 38.

The square root of 81085187 is about 9004.7313674534. The cubic root of 81085187 is about 432.8264980906.

The spelling of 81085187 in words is "eighty-one million, eighty-five thousand, one hundred eighty-seven".