209628 has 30 divisors (see below), whose sum is σ = 548856. Its totient is φ = 69768.

The previous prime is 209623. The next prime is 209639. The reversal of 209628 is 826902.

209628 is a nontrivial binomial coefficient, being equal to C(648, 2).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209621) by changing a digit.

209628 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 9 ways as a sum of consecutive naturals, for example, 1 + ... + 647.

2²⁰⁹⁶²⁸ is an apocalyptic number.

209628 is the 647-th triangular number and also the 324-th hexagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (274428).

209628 is an abundant number, since it is smaller than the sum of its proper divisors (339228).

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

209628 is a wasteful number, since it uses less digits than its factorization.

209628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 209628 is about 457.8515043112. The cubic root of 209628 is about 59.4041013391.

The spelling of 209628 in words is "two hundred nine thousand, six hundred twenty-eight".