209990 has 32 divisors (see below), whose sum is σ = 435456. Its totient is φ = 72160.

The previous prime is 209987. The next prime is 210011. The reversal of 209990 is 99902.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2489 + ... + 2571.

It is an arithmetic number, because the mean of its divisors is an integer number (13608).

2²⁰⁹⁹⁹⁰ is an apocalyptic number.

209990 is an abundant number, since it is smaller than the sum of its proper divisors (225466).

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

209990 is a wasteful number, since it uses less digits than its factorization.

209990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124.

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 209990 is about 458.2466584712. The cubic root of 209990 is about 59.4382760330.

The spelling of 209990 in words is "two hundred nine thousand, nine hundred ninety".