81671 has 2 divisors, whose sum is σ = 81672. Its totient is φ = 81670.

The previous prime is 81667. The next prime is 81677. The reversal of 81671 is 17618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81671 - 2² = 81667 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81671.

It is not a weakly prime, because it can be changed into another prime (81677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40835 + 40836.

It is an arithmetic number, because the mean of its divisors is an integer number (40836).

2⁸¹⁶⁷¹ is an apocalyptic number.

81671 is a deficient number, since it is larger than the sum of its proper divisors (1).

81671 is an equidigital number, since it uses as much as digits as its factorization.

81671 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 23.

The square root of 81671 is about 285.7813849781. The cubic root of 81671 is about 43.3866339524.

The spelling of 81671 in words is "eighty-one thousand, six hundred seventy-one".