1201809 has 16 divisors (see below), whose sum is σ = 1848320. Its totient is φ = 680400.

The previous prime is 1201793. The next prime is 1201813. The reversal of 1201809 is 9081021.

It is not a de Polignac number, because 1201809 - 2⁴ = 1201793 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1201829) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2982 + ... + 3360.

It is an arithmetic number, because the mean of its divisors is an integer number (115520).

2^1201809 is an apocalyptic number.

It is an amenable number.

1201809 is a deficient number, since it is larger than the sum of its proper divisors (646511).

1201809 is a wasteful number, since it uses less digits than its factorization.

1201809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 1201809 is about 1096.2704958175. The cubic root of 1201809 is about 106.3192287010.

The spelling of 1201809 in words is "one million, two hundred one thousand, eight hundred nine".