81458171 has 2 divisors, whose sum is σ = 81458172. Its totient is φ = 81458170.

The previous prime is 81458123. The next prime is 81458213. The reversal of 81458171 is 17185418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81458171 - 2²² = 77263867 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81458471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40729085 + 40729086.

It is an arithmetic number, because the mean of its divisors is an integer number (40729086).

Almost surely, 2^81458171 is an apocalyptic number.

81458171 is a deficient number, since it is larger than the sum of its proper divisors (1).

81458171 is an equidigital number, since it uses as much as digits as its factorization.

81458171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8960, while the sum is 35.

The square root of 81458171 is about 9025.4180512595. The cubic root of 81458171 is about 433.4891364142.

It can be divided in two parts, 814 and 58171, that added together give a palindrome (58985).

The spelling of 81458171 in words is "eighty-one million, four hundred fifty-eight thousand, one hundred seventy-one".