209940816 has 20 divisors (see below), whose sum is σ = 542347232. Its totient is φ = 69980256.

The previous prime is 209940811. The next prime is 209940817. The reversal of 209940816 is 618049902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209940811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2186836 + ... + 2186931.

Almost surely, 2^209940816 is an apocalyptic number.

It is an amenable number.

209940816 is an abundant number, since it is smaller than the sum of its proper divisors (332406416).

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

209940816 is a wasteful number, since it uses less digits than its factorization.

209940816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4373778 (or 4373772 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 209940816 is about 14489.3345602895. The cubic root of 209940816 is about 594.3363511287.

The spelling of 209940816 in words is "two hundred nine million, nine hundred forty thousand, eight hundred sixteen".