81515880173 has 8 divisors (see below), whose sum is σ = 100327237248. Its totient is φ = 64496080944.

The previous prime is 81515880161. The next prime is 81515880191. The reversal of 81515880173 is 37108851518.

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 81515880173 - 2¹⁰ = 81515879149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81515880143) 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, 447889361 + ... + 447889542.

It is an arithmetic number, because the mean of its divisors is an integer number (12540904656).

Almost surely, 2^81515880173 is an apocalyptic number.

It is an amenable number.

81515880173 is a deficient number, since it is larger than the sum of its proper divisors (18811357075).

81515880173 is a wasteful number, since it uses less digits than its factorization.

81515880173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 895778923.

The product of its (nonzero) digits is 268800, while the sum is 47.

The spelling of 81515880173 in words is "eighty-one billion, five hundred fifteen million, eight hundred eighty thousand, one hundred seventy-three".