81165056117 has 8 divisors (see below), whose sum is σ = 82384775352. Its totient is φ = 79953496000.

The previous prime is 81165056107. The next prime is 81165056153. The reversal of 81165056117 is 71165056118.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 74634961636 + 6530094481 = 273194^2 + 80809^2 .

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 81165056117 - 2⁴ = 81165056101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81165056107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2019734 + ... + 2059527.

It is an arithmetic number, because the mean of its divisors is an integer number (10298096919).

Almost surely, 2^81165056117 is an apocalyptic number.

It is an amenable number.

81165056117 is a deficient number, since it is larger than the sum of its proper divisors (1219719235).

81165056117 is a wasteful number, since it uses less digits than its factorization.

81165056117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4079559.

The product of its (nonzero) digits is 50400, while the sum is 41.

Subtracting from 81165056117 its reverse (71165056118), we obtain a palindrome (9999999999).

The spelling of 81165056117 in words is "eighty-one billion, one hundred sixty-five million, fifty-six thousand, one hundred seventeen".