81171943 has 4 divisors (see below), whose sum is σ = 81192760. Its totient is φ = 81151128.

The previous prime is 81171941. The next prime is 81171949. The reversal of 81171943 is 34917118.

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

It is a cyclic number.

It is not a de Polignac number, because 81171943 - 2¹ = 81171941 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81171899 and 81171908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81171941) 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, 2613 + ... + 13006.

It is an arithmetic number, because the mean of its divisors is an integer number (20298190).

Almost surely, 2^81171943 is an apocalyptic number.

81171943 is a deficient number, since it is larger than the sum of its proper divisors (20817).

81171943 is a wasteful number, since it uses less digits than its factorization.

81171943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20816.

The product of its digits is 6048, while the sum is 34.

The square root of 81171943 is about 9009.5473249215. The cubic root of 81171943 is about 432.9808086902.

The spelling of 81171943 in words is "eighty-one million, one hundred seventy-one thousand, nine hundred forty-three".