2100409 has 2 divisors, whose sum is σ = 2100410. Its totient is φ = 2100408.

The previous prime is 2100407. The next prime is 2100451. The reversal of 2100409 is 9040012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1155625 + 944784 = 1075^2 + 972^2 .

It is a cyclic number.

It is not a de Polignac number, because 2100409 - 2¹ = 2100407 is a prime.

Together with 2100407, it forms a pair of twin primes.

It is an Ulam number.

2100409 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2100392 and 2100401.

It is not a weakly prime, because it can be changed into another prime (2100403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050204 + 1050205.

It is an arithmetic number, because the mean of its divisors is an integer number (1050205).

2^2100409 is an apocalyptic number.

It is an amenable number.

2100409 is a deficient number, since it is larger than the sum of its proper divisors (1).

2100409 is an equidigital number, since it uses as much as digits as its factorization.

2100409 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 2100409 is about 1449.2787861554. The cubic root of 2100409 is about 128.0662295603.

The spelling of 2100409 in words is "two million, one hundred thousand, four hundred nine".