208409 has 2 divisors, whose sum is σ = 208410. Its totient is φ = 208408.

The previous prime is 208393. The next prime is 208433. The reversal of 208409 is 904802.

208409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144400 + 64009 = 380^2 + 253^2 .

It is a cyclic number.

It is not a de Polignac number, because 208409 - 2⁴ = 208393 is a prime.

It is a super-2 number, since 2×208409² = 86868622562, which contains 22 as substring.

It is equal to p₁₈₆₇₁ and since 208409 and 18671 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (208459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104204 + 104205.

It is an arithmetic number, because the mean of its divisors is an integer number (104205).

2²⁰⁸⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

208409 is a deficient number, since it is larger than the sum of its proper divisors (1).

208409 is an equidigital number, since it uses as much as digits as its factorization.

208409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 208409 is about 456.5183457431. The cubic root of 208409 is about 59.2887312264.

The spelling of 208409 in words is "two hundred eight thousand, four hundred nine".