201609 has 20 divisors (see below), whose sum is σ = 319440. Its totient is φ = 126360.

The previous prime is 201599. The next prime is 201611. The reversal of 201609 is 906102.

It is not a de Polignac number, because 201609 - 2⁵ = 201577 is a prime.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

201609 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 201591 and 201600.

It is not an unprimeable number, because it can be changed into a prime (201629) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1474 + ... + 1604.

It is an arithmetic number, because the mean of its divisors is an integer number (15972).

2²⁰¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

201609 is a deficient number, since it is larger than the sum of its proper divisors (117831).

201609 is a wasteful number, since it uses less digits than its factorization.

201609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 201609 is about 449.0089085976. The cubic root of 201609 is about 58.6367609000.

The spelling of 201609 in words is "two hundred one thousand, six hundred nine".