81137171 has 4 divisors (see below), whose sum is σ = 81175200. Its totient is φ = 81099144.

The previous prime is 81137159. The next prime is 81137179. The reversal of 81137171 is 17173118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17173118 = 2 ⋅8586559.

It is a cyclic number.

It is not a de Polignac number, because 81137171 - 2¹⁸ = 80875027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81137179) 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, 15611 + ... + 20148.

It is an arithmetic number, because the mean of its divisors is an integer number (20293800).

Almost surely, 2^81137171 is an apocalyptic number.

81137171 is a deficient number, since it is larger than the sum of its proper divisors (38029).

81137171 is a wasteful number, since it uses less digits than its factorization.

81137171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38028.

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

The square root of 81137171 is about 9007.6173875226. The cubic root of 81137171 is about 432.9189738639.

The spelling of 81137171 in words is "eighty-one million, one hundred thirty-seven thousand, one hundred seventy-one".