81863173 has 12 divisors (see below), whose sum is σ = 95738112. Its totient is φ = 69793080.

The previous prime is 81863161. The next prime is 81863209. The reversal of 81863173 is 37136818.

It is not a de Polignac number, because 81863173 - 2²¹ = 79766021 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 (81863113) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4986 + ... + 13732.

It is an arithmetic number, because the mean of its divisors is an integer number (7978176).

Almost surely, 2^81863173 is an apocalyptic number.

It is an amenable number.

81863173 is a deficient number, since it is larger than the sum of its proper divisors (13874939).

81863173 is a wasteful number, since it uses less digits than its factorization.

81863173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8952 (or 8945 counting only the distinct ones).

The product of its digits is 24192, while the sum is 37.

The square root of 81863173 is about 9047.8269766834. The cubic root of 81863173 is about 434.2063708093.

The spelling of 81863173 in words is "eighty-one million, eight hundred sixty-three thousand, one hundred seventy-three".