209939968 has 80 divisors (see below), whose sum is σ = 504789120. Its totient is φ = 85211136.

The previous prime is 209939921. The next prime is 209940041. The reversal of 209939968 is 869939902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66555 + ... + 69637.

It is an arithmetic number, because the mean of its divisors is an integer number (6309864).

Almost surely, 2^209939968 is an apocalyptic number.

209939968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209939968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252394560).

209939968 is an abundant number, since it is smaller than the sum of its proper divisors (294849152).

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

209939968 is an equidigital number, since it uses as much as digits as its factorization.

209939968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3127 (or 3111 counting only the distinct ones).

The product of its (nonzero) digits is 1889568, while the sum is 55.

The square root of 209939968 is about 14489.3052973564. The cubic root of 209939968 is about 594.3355509065.

The spelling of 209939968 in words is "two hundred nine million, nine hundred thirty-nine thousand, nine hundred sixty-eight".