81167971 has 2 divisors, whose sum is σ = 81167972. Its totient is φ = 81167970.

The previous prime is 81167959. The next prime is 81168001. The reversal of 81167971 is 17976118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81167971 - 2¹³ = 81159779 is a prime.

It is not a weakly prime, because it can be changed into another prime (81167171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40583985 + 40583986.

It is an arithmetic number, because the mean of its divisors is an integer number (40583986).

Almost surely, 2^81167971 is an apocalyptic number.

81167971 is a deficient number, since it is larger than the sum of its proper divisors (1).

81167971 is an equidigital number, since it uses as much as digits as its factorization.

81167971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 40.

The square root of 81167971 is about 9009.3268893963. The cubic root of 81167971 is about 432.9737462014.

The spelling of 81167971 in words is "eighty-one million, one hundred sixty-seven thousand, nine hundred seventy-one".