209872 has 20 divisors (see below), whose sum is σ = 438340. Its totient is φ = 96768.

The previous prime is 209861. The next prime is 209887. The reversal of 209872 is 278902.

209872 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 46656 + 163216 = 216^2 + 404^2 .

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 209872.

It is a congruent number.

It is an unprimeable number.

209872 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 297 + ... + 712.

It is an arithmetic number, because the mean of its divisors is an integer number (21917).

2²⁰⁹⁸⁷² is an apocalyptic number.

It is an amenable number.

209872 is an abundant number, since it is smaller than the sum of its proper divisors (228468).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209872 is a wasteful number, since it uses less digits than its factorization.

209872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1030 (or 1024 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 209872 is about 458.1178887579. The cubic root of 209872 is about 59.4271405333.

It can be divided in two parts, 209 and 872, that added together give a triangular number (1081 = T₄₆).

The spelling of 209872 in words is "two hundred nine thousand, eight hundred seventy-two".