81823171 has 2 divisors, whose sum is σ = 81823172. Its totient is φ = 81823170.

The previous prime is 81823151. The next prime is 81823199. The reversal of 81823171 is 17132818.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81823171 - 2¹¹ = 81821123 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81823141) 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, 40911585 + 40911586.

It is an arithmetic number, because the mean of its divisors is an integer number (40911586).

Almost surely, 2^81823171 is an apocalyptic number.

81823171 is a deficient number, since it is larger than the sum of its proper divisors (1).

81823171 is an equidigital number, since it uses as much as digits as its factorization.

81823171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 31.

The square root of 81823171 is about 9045.6161205304. The cubic root of 81823171 is about 434.1356350825.

Adding to 81823171 its reverse (17132818), we get a palindrome (98955989).

The spelling of 81823171 in words is "eighty-one million, eight hundred twenty-three thousand, one hundred seventy-one".