209992 has 8 divisors (see below), whose sum is σ = 393750. Its totient is φ = 104992.

The previous prime is 209987. The next prime is 210011. The reversal of 209992 is 299902.

It can be written as a sum of positive squares in only one way, i.e., 155236 + 54756 = 394^2 + 234^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a plaindrome in base 16.

It is a nialpdrome in base 8.

It is an unprimeable number.

209992 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13117 + ... + 13132.

2²⁰⁹⁹⁹² is an apocalyptic number.

It is an amenable number.

209992 is a deficient number, since it is larger than the sum of its proper divisors (183758).

209992 is a wasteful number, since it uses less digits than its factorization.

209992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26255 (or 26251 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 209992 is about 458.2488406968. The cubic root of 209992 is about 59.4384647343.

The spelling of 209992 in words is "two hundred nine thousand, nine hundred ninety-two".