71891 has 8 divisors (see below), whose sum is σ = 77520. Its totient is φ = 66528.

The previous prime is 71887. The next prime is 71899. The reversal of 71891 is 19817.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 71891 - 2² = 71887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71891.

It is not an unprimeable number, because it can be changed into a prime (71899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1040 + ... + 1106.

It is an arithmetic number, because the mean of its divisors is an integer number (9690).

2⁷¹⁸⁹¹ is an apocalyptic number.

71891 is a deficient number, since it is larger than the sum of its proper divisors (5629).

71891 is a wasteful number, since it uses less digits than its factorization.

71891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133.

The product of its digits is 504, while the sum is 26.

The square root of 71891 is about 268.1249708625. The cubic root of 71891 is about 41.5806724196.

Adding to 71891 its sum of digits (26), we get a palindrome (71917).

The spelling of 71891 in words is "seventy-one thousand, eight hundred ninety-one".