81317686317672 has 192 divisors, whose sum is σ = 237578299845120. Its totient is φ = 23126451167232.

The previous prime is 81317686317661. The next prime is 81317686317677. The reversal of 81317686317672 is 27671368671318.

It is a super-3 number, since 3×81317686317672³ (a number of 43 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a nude number because it is divisible by every one of its digits.

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 47 ways as a sum of consecutive naturals, for example, 240392368 + ... + 240730400.

It is an arithmetic number, because the mean of its divisors is an integer number (1237386978360).

Almost surely, 2^{81317686317672} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81317686317672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118789149922560).

81317686317672 is an abundant number, since it is smaller than the sum of its proper divisors (156260613527448).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81317686317672 is a wasteful number, since it uses less digits than its factorization.

81317686317672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339000 (or 338989 counting only the distinct ones).

The product of its digits is 85349376, while the sum is 66.

The spelling of 81317686317672 in words is "eighty-one trillion, three hundred seventeen billion, six hundred eighty-six million, three hundred seventeen thousand, six hundred seventy-two".