81202171 has 2 divisors, whose sum is σ = 81202172. Its totient is φ = 81202170.

The previous prime is 81202159. The next prime is 81202243. The reversal of 81202171 is 17120218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81202171 - 2²⁵ = 47647739 is a prime.

It is a super-2 number, since 2×81202171² = 13187585150226482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81202111) 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, 40601085 + 40601086.

It is an arithmetic number, because the mean of its divisors is an integer number (40601086).

Almost surely, 2^81202171 is an apocalyptic number.

81202171 is a deficient number, since it is larger than the sum of its proper divisors (1).

81202171 is an equidigital number, since it uses as much as digits as its factorization.

81202171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 81202171 is about 9011.2247225336. The cubic root of 81202171 is about 433.0345486037.

Adding to 81202171 its reverse (17120218), we get a palindrome (98322389).

It can be divided in two parts, 8120217 and 1, that added together give a palindrome (8120218).

The spelling of 81202171 in words is "eighty-one million, two hundred two thousand, one hundred seventy-one".