2101409 has 4 divisors (see below), whose sum is σ = 2107716. Its totient is φ = 2095104.

The previous prime is 2101391. The next prime is 2101423. The reversal of 2101409 is 9041012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 305809 + 1795600 = 553^2 + 1340^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2101409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2101439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2624 + ... + 3329.

It is an arithmetic number, because the mean of its divisors is an integer number (526929).

2^2101409 is an apocalyptic number.

It is an amenable number.

2101409 is a deficient number, since it is larger than the sum of its proper divisors (6307).

2101409 is an equidigital number, since it uses as much as digits as its factorization.

2101409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6306.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 2101409 is about 1449.6237442868. The cubic root of 2101409 is about 128.0865503504.

The spelling of 2101409 in words is "two million, one hundred one thousand, four hundred nine".