209887 has 2 divisors, whose sum is σ = 209888. Its totient is φ = 209886.

The previous prime is 209861. The next prime is 209917. The reversal of 209887 is 788902.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209887 is a prime.

209887 is a lucky number.

It is a plaindrome in base 14 and base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104943 + 104944.

It is an arithmetic number, because the mean of its divisors is an integer number (104944).

2²⁰⁹⁸⁸⁷ is an apocalyptic number.

209887 is a deficient number, since it is larger than the sum of its proper divisors (1).

209887 is an equidigital number, since it uses as much as digits as its factorization.

209887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 209887 is about 458.1342597973. The cubic root of 209887 is about 59.4285562945.

The spelling of 209887 in words is "two hundred nine thousand, eight hundred eighty-seven".