209839919 has 2 divisors, whose sum is σ = 209839920. Its totient is φ = 209839918.

The previous prime is 209839901. The next prime is 209839951. The reversal of 209839919 is 919938902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209839919 is a prime.

It is a super-2 number, since 2×209839919² = 88065583211853122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209839999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104919959 + 104919960.

It is an arithmetic number, because the mean of its divisors is an integer number (104919960).

Almost surely, 2^209839919 is an apocalyptic number.

209839919 is a deficient number, since it is larger than the sum of its proper divisors (1).

209839919 is an equidigital number, since it uses as much as digits as its factorization.

209839919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 314928, while the sum is 50.

The square root of 209839919 is about 14485.8523739544. The cubic root of 209839919 is about 594.2411237131.

The spelling of 209839919 in words is "two hundred nine million, eight hundred thirty-nine thousand, nine hundred nineteen".