71309 has 8 divisors (see below), whose sum is σ = 83328. Its totient is φ = 59760.

The previous prime is 71293. The next prime is 71317. The reversal of 71309 is 90317.

71309 = T₃₆ + T₃₇ + ... + T₇₇.

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

It is a cyclic number.

It is not a de Polignac number, because 71309 - 2⁴ = 71293 is a prime.

It is a Curzon number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 344 + ... + 510.

It is an arithmetic number, because the mean of its divisors is an integer number (10416).

2⁷¹³⁰⁹ is an apocalyptic number.

It is an amenable number.

71309 is a deficient number, since it is larger than the sum of its proper divisors (12019).

71309 is a wasteful number, since it uses less digits than its factorization.

71309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235.

The product of its (nonzero) digits is 189, while the sum is 20.

The square root of 71309 is about 267.0374505570. The cubic root of 71309 is about 41.4681615771.

Subtracting from 71309 its sum of digits (20), we obtain a square (71289 = 267²).

The spelling of 71309 in words is "seventy-one thousand, three hundred nine".