71609 has 4 divisors (see below), whose sum is σ = 72420. Its totient is φ = 70800.

The previous prime is 71597. The next prime is 71633. The reversal of 71609 is 90617.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 42025 + 29584 = 205^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 71609 - 2⁴ = 71593 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71699) 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, 254 + ... + 455.

It is an arithmetic number, because the mean of its divisors is an integer number (18105).

2⁷¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

71609 is a deficient number, since it is larger than the sum of its proper divisors (811).

71609 is a wasteful number, since it uses less digits than its factorization.

71609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 71609 is about 267.5985799663. The cubic root of 71609 is about 41.5262329907.

The spelling of 71609 in words is "seventy-one thousand, six hundred nine".