209017128 has 64 divisors (see below), whose sum is σ = 541440000. Its totient is φ = 67170240.

The previous prime is 209017121. The next prime is 209017129. The reversal of 209017128 is 821710902.

It is a junction number, because it is equal to n+sod(n) for n = 209017095 and 209017104.

It is not an unprimeable number, because it can be changed into a prime (209017121) 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 15 ways as a sum of consecutive naturals, for example, 370975 + ... + 371537.

It is an arithmetic number, because the mean of its divisors is an integer number (8460000).

Almost surely, 2^209017128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209017128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (270720000).

209017128 is an abundant number, since it is smaller than the sum of its proper divisors (332422872).

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

209017128 is a wasteful number, since it uses less digits than its factorization.

209017128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102 (or 1098 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 209017128 is about 14457.4246669315. The cubic root of 209017128 is about 593.4634250228.

The spelling of 209017128 in words is "two hundred nine million, seventeen thousand, one hundred twenty-eight".