81673845 has 32 divisors (see below), whose sum is σ = 146047104. Its totient is φ = 38630400.

The previous prime is 81673843. The next prime is 81673853. The reversal of 81673845 is 54837618.

It is not a de Polignac number, because 81673845 - 2¹ = 81673843 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81673797 and 81673806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81673843) 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 in 31 ways as a sum of consecutive naturals, for example, 729 + ... + 12801.

It is an arithmetic number, because the mean of its divisors is an integer number (4563972).

Almost surely, 2^81673845 is an apocalyptic number.

It is an amenable number.

81673845 is a deficient number, since it is larger than the sum of its proper divisors (64373259).

81673845 is a wasteful number, since it uses less digits than its factorization.

81673845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12133.

The product of its digits is 161280, while the sum is 42.

The square root of 81673845 is about 9037.3582976443. The cubic root of 81673845 is about 433.8713773601.

The spelling of 81673845 in words is "eighty-one million, six hundred seventy-three thousand, eight hundred forty-five".