81665011 has 2 divisors, whose sum is σ = 81665012. Its totient is φ = 81665010.

The previous prime is 81664967. The next prime is 81665033. The reversal of 81665011 is 11056618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81665011 - 2¹¹ = 81662963 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81665081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40832505 + 40832506.

It is an arithmetic number, because the mean of its divisors is an integer number (40832506).

Almost surely, 2^81665011 is an apocalyptic number.

81665011 is a deficient number, since it is larger than the sum of its proper divisors (1).

81665011 is an equidigital number, since it uses as much as digits as its factorization.

81665011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 81665011 is about 9036.8695354088. The cubic root of 81665011 is about 433.8557340088.

The spelling of 81665011 in words is "eighty-one million, six hundred sixty-five thousand, eleven".