81317157420881 has 8 divisors (see below), whose sum is σ = 83940535948800. Its totient is φ = 78693794169120.

The previous prime is 81317157420857. The next prime is 81317157420899. The reversal of 81317157420881 is 18802475171318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81317157420881 is a prime.

It is a super-2 number, since 2×81317157420881² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81317157420841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7534805 + ... + 14812413.

It is an arithmetic number, because the mean of its divisors is an integer number (10492566993600).

Almost surely, 2^{81317157420881} is an apocalyptic number.

It is an amenable number.

81317157420881 is a deficient number, since it is larger than the sum of its proper divisors (2623378527919).

81317157420881 is a wasteful number, since it uses less digits than its factorization.

81317157420881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7638079.

The product of its (nonzero) digits is 3010560, while the sum is 56.

The spelling of 81317157420881 in words is "eighty-one trillion, three hundred seventeen billion, one hundred fifty-seven million, four hundred twenty thousand, eight hundred eighty-one".