81317686317673 has 4 divisors (see below), whose sum is σ = 87572892957508. Its totient is φ = 75062479677840.

The previous prime is 81317686317661. The next prime is 81317686317677. The reversal of 81317686317673 is 37671368671318.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12478605705049 + 68839080612624 = 3532507^2 + 8296932^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81317686317673 is a prime.

It is a super-2 number, since 2×81317686317673² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81317686317599 and 81317686317608.

It is not an unprimeable number, because it can be changed into a prime (81317686317677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3127603319898 + ... + 3127603319923.

It is an arithmetic number, because the mean of its divisors is an integer number (21893223239377).

Almost surely, 2^{81317686317673} is an apocalyptic number.

It is an amenable number.

81317686317673 is a deficient number, since it is larger than the sum of its proper divisors (6255206639835).

81317686317673 is a wasteful number, since it uses less digits than its factorization.

81317686317673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6255206639834.

The product of its digits is 128024064, while the sum is 67.

The spelling of 81317686317673 in words is "eighty-one trillion, three hundred seventeen billion, six hundred eighty-six million, three hundred seventeen thousand, six hundred seventy-three".