209428 has 12 divisors (see below), whose sum is σ = 375732. Its totient is φ = 102080.

The previous prime is 209401. The next prime is 209431. The reversal of 209428 is 824902.

It can be written as a sum of positive squares in 2 ways, for example, as 63504 + 145924 = 252^2 + 382^2 .

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

209428 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 in 3 ways as a sum of consecutive naturals, for example, 475 + ... + 802.

It is an arithmetic number, because the mean of its divisors is an integer number (31311).

2²⁰⁹⁴²⁸ is an apocalyptic number.

It is an amenable number.

209428 is a deficient number, since it is larger than the sum of its proper divisors (166304).

209428 is a wasteful number, since it uses less digits than its factorization.

209428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1322 (or 1320 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 209428 is about 457.6330407652. The cubic root of 209428 is about 59.3852034173.

The spelling of 209428 in words is "two hundred nine thousand, four hundred twenty-eight".