201605 has 8 divisors (see below), whose sum is σ = 246264. Its totient is φ = 158400.

The previous prime is 201599. The next prime is 201611. The reversal of 201605 is 506102.

It is an interprime number because it is at equal distance from previous prime (201599) and next prime (201611).

It can be written as a sum of positive squares in 4 ways, for example, as 6241 + 195364 = 79^2 + 442^2 .

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

It is not a de Polignac number, because 201605 - 2⁴ = 201589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 201605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26 + ... + 635.

It is an arithmetic number, because the mean of its divisors is an integer number (30783).

2²⁰¹⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

201605 is a deficient number, since it is larger than the sum of its proper divisors (44659).

201605 is an equidigital number, since it uses as much as digits as its factorization.

201605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 201605 is about 449.0044543209. The cubic root of 201605 is about 58.6363731055.

Adding to 201605 its reverse (506102), we get a palindrome (707707).

The spelling of 201605 in words is "two hundred one thousand, six hundred five".