209940109 has 8 divisors (see below), whose sum is σ = 216156920. Its totient is φ = 203751936.

The previous prime is 209940103. The next prime is 209940121. The reversal of 209940109 is 901049902.

209940109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 117722500 + 92217609 = 10850^2 + 9603^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 209940109 - 2¹¹ = 209938061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209940103) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8197 + ... + 22069.

It is an arithmetic number, because the mean of its divisors is an integer number (27019615).

Almost surely, 2^209940109 is an apocalyptic number.

It is an amenable number.

209940109 is a deficient number, since it is larger than the sum of its proper divisors (6216811).

209940109 is a wasteful number, since it uses less digits than its factorization.

209940109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14319.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 209940109 is about 14489.3101630133. The cubic root of 209940109 is about 594.3356839625.

The spelling of 209940109 in words is "two hundred nine million, nine hundred forty thousand, one hundred nine".