81271111 has 2 divisors, whose sum is σ = 81271112. Its totient is φ = 81271110.

The previous prime is 81271063. The next prime is 81271117. The reversal of 81271111 is 11117218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81271111 - 2⁹ = 81270599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81271117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40635555 + 40635556.

It is an arithmetic number, because the mean of its divisors is an integer number (40635556).

Almost surely, 2^81271111 is an apocalyptic number.

81271111 is a deficient number, since it is larger than the sum of its proper divisors (1).

81271111 is an equidigital number, since it uses as much as digits as its factorization.

81271111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112, while the sum is 22.

The square root of 81271111 is about 9015.0491401878. The cubic root of 81271111 is about 433.1570615733.

Adding to 81271111 its reverse (11117218), we get a palindrome (92388329).

The spelling of 81271111 in words is "eighty-one million, two hundred seventy-one thousand, one hundred eleven".