201009 has 4 divisors (see below), whose sum is σ = 268016. Its totient is φ = 134004.

The previous prime is 201007. The next prime is 201011. The reversal of 201009 is 900102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (201007) and next prime (201011).

It is not a de Polignac number, because 201009 - 2¹ = 201007 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 200985 and 201003.

It is not an unprimeable number, because it can be changed into a prime (201007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33499 + ... + 33504.

It is an arithmetic number, because the mean of its divisors is an integer number (67004).

2²⁰¹⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

201009 is a deficient number, since it is larger than the sum of its proper divisors (67007).

201009 is an equidigital number, since it uses as much as digits as its factorization.

201009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67006.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 201009 is about 448.3402725609. The cubic root of 201009 is about 58.5785343069.

The spelling of 201009 in words is "two hundred one thousand, nine".