71009 has 4 divisors (see below), whose sum is σ = 75204. Its totient is φ = 66816.

The previous prime is 70999. The next prime is 71011. The reversal of 71009 is 90017.

71009 is nontrivially palindromic in base 11.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 61009 + 10000 = 247^2 + 100^2 .

It is a cyclic number.

It is not a de Polignac number, because 71009 - 2⁸ = 70753 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 4177 = 71009 / (7 + 1 + 0 + 0 + 9).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71039) 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 3 ways as a sum of consecutive naturals, for example, 2072 + ... + 2105.

It is an arithmetic number, because the mean of its divisors is an integer number (18801).

2⁷¹⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

71009 is a deficient number, since it is larger than the sum of its proper divisors (4195).

71009 is a wasteful number, since it uses less digits than its factorization.

71009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4194.

The product of its (nonzero) digits is 63, while the sum is 17.

The square root of 71009 is about 266.4751395534. The cubic root of 71009 is about 41.4099270616.

The spelling of 71009 in words is "seventy-one thousand, nine".