71905 has 8 divisors (see below), whose sum is σ = 87912. Its totient is φ = 56448.

The previous prime is 71899. The next prime is 71909. The reversal of 71905 is 50917.

71905 is nontrivially palindromic in base 13 and base 14.

It can be written as a sum of positive squares in 4 ways, for example, as 28224 + 43681 = 168^2 + 209^2 .

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

It is a 2-Lehmer number, since φ(71905) divides (71905-1)².

It is a cyclic number.

It is not a de Polignac number, because 71905 - 2⁷ = 71777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 267 + ... + 463.

It is an arithmetic number, because the mean of its divisors is an integer number (10989).

2⁷¹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

71905 is a deficient number, since it is larger than the sum of its proper divisors (16007).

71905 is a wasteful number, since it uses less digits than its factorization.

71905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275.

The product of its (nonzero) digits is 315, while the sum is 22.

The square root of 71905 is about 268.1510768205. The cubic root of 71905 is about 41.5833713742.

The spelling of 71905 in words is "seventy-one thousand, nine hundred five".