81685163 has 8 divisors (see below), whose sum is σ = 93419232. Its totient is φ = 69967296.

The previous prime is 81685147. The next prime is 81685171. The reversal of 81685163 is 36158618.

It is a happy number.

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

It is not a de Polignac number, because 81685163 - 2⁴ = 81685147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81685133) 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, 10031 + ... + 16247.

It is an arithmetic number, because the mean of its divisors is an integer number (11677404).

Almost surely, 2^81685163 is an apocalyptic number.

81685163 is a deficient number, since it is larger than the sum of its proper divisors (11734069).

81685163 is a wasteful number, since it uses less digits than its factorization.

81685163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8101.

The product of its digits is 34560, while the sum is 38.

The square root of 81685163 is about 9037.9844545120. The cubic root of 81685163 is about 433.8914177596.

It can be divided in two parts, 8168 and 5163, that added together give a palindrome (13331).

The spelling of 81685163 in words is "eighty-one million, six hundred eighty-five thousand, one hundred sixty-three".