81673665782205 has 64 divisors (see below), whose sum is σ = 149505077145600. Its totient is φ = 37296803496960.

The previous prime is 81673665782171. The next prime is 81673665782207. The reversal of 81673665782205 is 50228756637618.

It is not a de Polignac number, because 81673665782205 - 2⁸ = 81673665781949 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81673665782207) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1405012581 + ... + 1405070709.

It is an arithmetic number, because the mean of its divisors is an integer number (2336016830400).

Almost surely, 2^{81673665782205} is an apocalyptic number.

It is an amenable number.

81673665782205 is a deficient number, since it is larger than the sum of its proper divisors (67831411363395).

81673665782205 is a wasteful number, since it uses less digits than its factorization.

81673665782205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72154.

The product of its (nonzero) digits is 203212800, while the sum is 66.

The spelling of 81673665782205 in words is "eighty-one trillion, six hundred seventy-three billion, six hundred sixty-five million, seven hundred eighty-two thousand, two hundred five".