209890 has 16 divisors (see below), whose sum is σ = 383040. Its totient is φ = 82800.

The previous prime is 209887. The next prime is 209917. The reversal of 209890 is 98902.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1315 + ... + 1465.

It is an arithmetic number, because the mean of its divisors is an integer number (23940).

2²⁰⁹⁸⁹⁰ is an apocalyptic number.

209890 is a deficient number, since it is larger than the sum of its proper divisors (173150).

209890 is a wasteful number, since it uses less digits than its factorization.

209890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 209890 is about 458.1375339350. The cubic root of 209890 is about 59.4288394386.

The spelling of 209890 in words is "two hundred nine thousand, eight hundred ninety".