219409 has 2 divisors, whose sum is σ = 219410. Its totient is φ = 219408.

The previous prime is 219407. The next prime is 219433. The reversal of 219409 is 904912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199809 + 19600 = 447^2 + 140^2 .

It is a cyclic number.

It is not a de Polignac number, because 219409 - 2¹ = 219407 is a prime.

Together with 219407, it forms a pair of twin primes.

219409 is a lucky number.

It is a nialpdrome in base 8.

It is not a weakly prime, because it can be changed into another prime (219407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109704 + 109705.

It is an arithmetic number, because the mean of its divisors is an integer number (109705).

2²¹⁹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

219409 is a deficient number, since it is larger than the sum of its proper divisors (1).

219409 is an equidigital number, since it uses as much as digits as its factorization.

219409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 219409 is about 468.4111441885. The cubic root of 219409 is about 60.3140019940.

The spelling of 219409 in words is "two hundred nineteen thousand, four hundred nine".