81518117 has 8 divisors (see below), whose sum is σ = 83047680. Its totient is φ = 79993600.

The previous prime is 81518083. The next prime is 81518123. The reversal of 81518117 is 71181518.

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 81518117 - 2¹² = 81514021 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 (81518147) 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, 50117 + ... + 51717.

It is an arithmetic number, because the mean of its divisors is an integer number (10380960).

Almost surely, 2^81518117 is an apocalyptic number.

It is an amenable number.

81518117 is a deficient number, since it is larger than the sum of its proper divisors (1529563).

81518117 is a wasteful number, since it uses less digits than its factorization.

81518117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2523.

The product of its digits is 2240, while the sum is 32.

The square root of 81518117 is about 9028.7383947039. The cubic root of 81518117 is about 433.5954468784.

The spelling of 81518117 in words is "eighty-one million, five hundred eighteen thousand, one hundred seventeen".