2001409 has 2 divisors, whose sum is σ = 2001410. Its totient is φ = 2001408.

The previous prime is 2001407. The next prime is 2001413. The reversal of 2001409 is 9041002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1882384 + 119025 = 1372^2 + 345^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001409 - 2¹ = 2001407 is a prime.

Together with 2001407, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2001392 and 2001401.

It is not a weakly prime, because it can be changed into another prime (2001407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000704 + 1000705.

It is an arithmetic number, because the mean of its divisors is an integer number (1000705).

2^2001409 is an apocalyptic number.

It is an amenable number.

2001409 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001409 is an equidigital number, since it uses as much as digits as its factorization.

2001409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 2001409 is about 1414.7116313935. The cubic root of 2001409 is about 126.0216851901.

The spelling of 2001409 in words is "two million, one thousand, four hundred nine".