71865 has 12 divisors (see below), whose sum is σ = 124644. Its totient is φ = 38304.

The previous prime is 71861. The next prime is 71867. The reversal of 71865 is 56817.

71865 = 38² + 39² + ... + 64².

It can be written as a sum of positive squares in 2 ways, for example, as 19881 + 51984 = 141^2 + 228^2 .

It is not a de Polignac number, because 71865 - 2² = 71861 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (71861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 754 + ... + 843.

It is an arithmetic number, because the mean of its divisors is an integer number (10387).

2⁷¹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

71865 is a deficient number, since it is larger than the sum of its proper divisors (52779).

71865 is a wasteful number, since it uses less digits than its factorization.

71865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608 (or 1605 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 71865 is about 268.0764816242. The cubic root of 71865 is about 41.5756591456.

The spelling of 71865 in words is "seventy-one thousand, eight hundred sixty-five".