81117173 has 4 divisors (see below), whose sum is σ = 83733888. Its totient is φ = 78500460.

The previous prime is 81117161. The next prime is 81117187. The reversal of 81117173 is 37171118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81117173 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 (81117133) 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 3 ways as a sum of consecutive naturals, for example, 1308311 + ... + 1308372.

It is an arithmetic number, because the mean of its divisors is an integer number (20933472).

Almost surely, 2^81117173 is an apocalyptic number.

It is an amenable number.

81117173 is a deficient number, since it is larger than the sum of its proper divisors (2616715).

81117173 is a wasteful number, since it uses less digits than its factorization.

81117173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2616714.

The product of its digits is 1176, while the sum is 29.

The square root of 81117173 is about 9006.5072586436. The cubic root of 81117173 is about 432.8834035455.

The spelling of 81117173 in words is "eighty-one million, one hundred seventeen thousand, one hundred seventy-three".