81917334161 has 8 divisors (see below), whose sum is σ = 88267675944. Its totient is φ = 75573993600.

The previous prime is 81917334151. The next prime is 81917334253. The reversal of 81917334161 is 16143371918.

It can be written as a sum of positive squares in 4 ways, for example, as 74995600 + 81842338561 = 8660^2 + 286081^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81917334161 - 2⁶ = 81917334097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81917334151) 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, 1725986 + ... + 1772811.

It is an arithmetic number, because the mean of its divisors is an integer number (11033459493).

Almost surely, 2^81917334161 is an apocalyptic number.

It is an amenable number.

81917334161 is a deficient number, since it is larger than the sum of its proper divisors (6350341783).

81917334161 is a wasteful number, since it uses less digits than its factorization.

81917334161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3500611.

The product of its digits is 108864, while the sum is 44.

The spelling of 81917334161 in words is "eighty-one billion, nine hundred seventeen million, three hundred thirty-four thousand, one hundred sixty-one".