81367173 has 20 divisors (see below), whose sum is σ = 121806828. Its totient is φ = 54129600.

The previous prime is 81367163. The next prime is 81367211. The reversal of 81367173 is 37176318.

It can be written as a sum of positive squares in 2 ways, for example, as 68856804 + 12510369 = 8298^2 + 3537^2 .

It is not a de Polignac number, because 81367173 - 2⁶ = 81367109 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81367103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 56065 + ... + 57497.

Almost surely, 2^81367173 is an apocalyptic number.

It is an amenable number.

81367173 is a deficient number, since it is larger than the sum of its proper divisors (40439655).

81367173 is a wasteful number, since it uses less digits than its factorization.

81367173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146 (or 2137 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 81367173 is about 9020.3754356457. The cubic root of 81367173 is about 433.3276574536.

The spelling of 81367173 in words is "eighty-one million, three hundred sixty-seven thousand, one hundred seventy-three".