71681 has 4 divisors (see below), whose sum is σ = 73392. Its totient is φ = 69972.

The previous prime is 71671. The next prime is 71693. The reversal of 71681 is 18617.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 71681 - 2¹⁰ = 70657 is a prime.

It is a super-2 number, since 2×71681² = 10276331522, which contains 22 as substring.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 71681.

It is not an unprimeable number, because it can be changed into a prime (71671) 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, 791 + ... + 876.

It is an arithmetic number, because the mean of its divisors is an integer number (18348).

It is a Proth number, since it is equal to 35 ⋅ 2¹¹ + 1 and 35 < 2¹¹.

2⁷¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

71681 is a deficient number, since it is larger than the sum of its proper divisors (1711).

71681 is a wasteful number, since it uses less digits than its factorization.

71681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1710.

The product of its digits is 336, while the sum is 23.

The square root of 71681 is about 267.7330760291. The cubic root of 71681 is about 41.5401459871.

It can be divided in two parts, 716 and 81, that added together give a palindrome (797).

The spelling of 71681 in words is "seventy-one thousand, six hundred eighty-one".