71931 has 4 divisors (see below), whose sum is σ = 95912. Its totient is φ = 47952.

The previous prime is 71917. The next prime is 71933. The reversal of 71931 is 13917.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13917 = 3 ⋅4639.

It is not a de Polignac number, because 71931 - 2⁵ = 71899 is a prime.

It is a super-2 number, since 2×71931² = 10348137522, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

71931 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 71898 and 71907.

It is not an unprimeable number, because it can be changed into a prime (71933) 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, 11986 + ... + 11991.

It is an arithmetic number, because the mean of its divisors is an integer number (23978).

2⁷¹⁹³¹ is an apocalyptic number.

71931 is a deficient number, since it is larger than the sum of its proper divisors (23981).

71931 is a wasteful number, since it uses less digits than its factorization.

71931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23980.

The product of its digits is 189, while the sum is 21.

The square root of 71931 is about 268.1995525723. The cubic root of 71931 is about 41.5883827891.

The spelling of 71931 in words is "seventy-one thousand, nine hundred thirty-one".