81973 has 2 divisors, whose sum is σ = 81974. Its totient is φ = 81972.

The previous prime is 81971. The next prime is 82003. The reversal of 81973 is 37918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58564 + 23409 = 242^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 81973 - 2¹ = 81971 is a prime.

Together with 81971, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40986 + 40987.

It is an arithmetic number, because the mean of its divisors is an integer number (40987).

2⁸¹⁹⁷³ is an apocalyptic number.

It is an amenable number.

81973 is a deficient number, since it is larger than the sum of its proper divisors (1).

81973 is an equidigital number, since it uses as much as digits as its factorization.

81973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 28.

The square root of 81973 is about 286.3092733392. The cubic root of 81973 is about 43.4400460009.

The spelling of 81973 in words is "eighty-one thousand, nine hundred seventy-three".