81673665782207 has 2 divisors, whose sum is σ = 81673665782208. Its totient is φ = 81673665782206.

The previous prime is 81673665782171. The next prime is 81673665782209. The reversal of 81673665782207 is 70228756637618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81673665782207 - 2⁶ = 81673665782143 is a prime.

Together with 81673665782209, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81673665782209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40836832891103 + 40836832891104.

It is an arithmetic number, because the mean of its divisors is an integer number (40836832891104).

Almost surely, 2^{81673665782207} is an apocalyptic number.

81673665782207 is a deficient number, since it is larger than the sum of its proper divisors (1).

81673665782207 is an equidigital number, since it uses as much as digits as its factorization.

81673665782207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 284497920, while the sum is 68.

The spelling of 81673665782207 in words is "eighty-one trillion, six hundred seventy-three billion, six hundred sixty-five million, seven hundred eighty-two thousand, two hundred seven".