81011173 has 4 divisors (see below), whose sum is σ = 81116748. Its totient is φ = 80905600.

The previous prime is 81011149. The next prime is 81011197. The reversal of 81011173 is 37111018.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (81011149) and next prime (81011197).

It can be written as a sum of positive squares in 2 ways, for example, as 38526849 + 42484324 = 6207^2 + 6518^2 .

It is a cyclic number.

It is not a de Polignac number, because 81011173 - 2¹³ = 81002981 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 (81011113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51628 + ... + 53173.

It is an arithmetic number, because the mean of its divisors is an integer number (20279187).

Almost surely, 2^81011173 is an apocalyptic number.

It is an amenable number.

81011173 is a deficient number, since it is larger than the sum of its proper divisors (105575).

81011173 is a wasteful number, since it uses less digits than its factorization.

81011173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105574.

The product of its (nonzero) digits is 168, while the sum is 22.

The square root of 81011173 is about 9000.6207008184. The cubic root of 81011173 is about 432.6947643189.

The spelling of 81011173 in words is "eighty-one million, eleven thousand, one hundred seventy-three".