2001509 has 2 divisors, whose sum is σ = 2001510. Its totient is φ = 2001508.

The previous prime is 2001487. The next prime is 2001511. The reversal of 2001509 is 9051002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1876900 + 124609 = 1370^2 + 353^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001509 - 2²⁰ = 952933 is a prime.

It is a Sophie Germain prime.

Together with 2001511, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000754 + 1000755.

It is an arithmetic number, because the mean of its divisors is an integer number (1000755).

2^2001509 is an apocalyptic number.

It is an amenable number.

2001509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001509 is an equidigital number, since it uses as much as digits as its factorization.

2001509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 2001509 is about 1414.7469738437. The cubic root of 2001509 is about 126.0237840379.

The spelling of 2001509 in words is "two million, one thousand, five hundred nine".