209617989 has 8 divisors (see below), whose sum is σ = 319417920. Its totient is φ = 119781696.

The previous prime is 209617963. The next prime is 209617999. The reversal of 209617989 is 989716902.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 209617989 - 2¹³ = 209609797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209617999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4990884 + ... + 4990925.

It is an arithmetic number, because the mean of its divisors is an integer number (39927240).

Almost surely, 2^209617989 is an apocalyptic number.

It is an amenable number.

209617989 is a deficient number, since it is larger than the sum of its proper divisors (109799931).

209617989 is an equidigital number, since it uses as much as digits as its factorization.

209617989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9981819.

The product of its (nonzero) digits is 489888, while the sum is 51.

The square root of 209617989 is about 14478.1901147899. The cubic root of 209617989 is about 594.0315568946.

The spelling of 209617989 in words is "two hundred nine million, six hundred seventeen thousand, nine hundred eighty-nine".