209940 has 24 divisors (see below), whose sum is σ = 588000. Its totient is φ = 55968.

The previous prime is 209939. The next prime is 209953. The reversal of 209940 is 49902.

It is a self number, because there is not a number n which added to its sum of digits gives 209940.

It is a congruent number.

It is an unprimeable 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 in 7 ways as a sum of consecutive naturals, for example, 1690 + ... + 1809.

It is an arithmetic number, because the mean of its divisors is an integer number (24500).

2²⁰⁹⁹⁴⁰ is an apocalyptic number.

209940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209940 is an abundant number, since it is smaller than the sum of its proper divisors (378060).

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

209940 is a wasteful number, since it uses less digits than its factorization.

209940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3511 (or 3509 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 209940 is about 458.1920994517. The cubic root of 209940 is about 59.4335581104.

The spelling of 209940 in words is "two hundred nine thousand, nine hundred forty".