81673843 has 2 divisors, whose sum is σ = 81673844. Its totient is φ = 81673842.

The previous prime is 81673807. The next prime is 81673853. The reversal of 81673843 is 34837618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81673843 - 2⁹ = 81673331 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81673796 and 81673805.

It is not a weakly prime, because it can be changed into another prime (81673853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40836921 + 40836922.

It is an arithmetic number, because the mean of its divisors is an integer number (40836922).

Almost surely, 2^81673843 is an apocalyptic number.

81673843 is a deficient number, since it is larger than the sum of its proper divisors (1).

81673843 is an equidigital number, since it uses as much as digits as its factorization.

81673843 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 40.

The square root of 81673843 is about 9037.3581869925. The cubic root of 81673843 is about 433.8713738186.

The spelling of 81673843 in words is "eighty-one million, six hundred seventy-three thousand, eight hundred forty-three".