81019171 has 2 divisors, whose sum is σ = 81019172. Its totient is φ = 81019170.

The previous prime is 81019121. The next prime is 81019189. The reversal of 81019171 is 17191018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81019171 - 2¹⁵ = 80986403 is a prime.

It is not a weakly prime, because it can be changed into another prime (81019121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40509585 + 40509586.

It is an arithmetic number, because the mean of its divisors is an integer number (40509586).

Almost surely, 2^81019171 is an apocalyptic number.

81019171 is a deficient number, since it is larger than the sum of its proper divisors (1).

81019171 is an equidigital number, since it uses as much as digits as its factorization.

81019171 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 28.

The square root of 81019171 is about 9001.0649925439. The cubic root of 81019171 is about 432.7090034199.

The spelling of 81019171 in words is "eighty-one million, nineteen thousand, one hundred seventy-one".