209940073 has 4 divisors (see below), whose sum is σ = 239931520. Its totient is φ = 179948628.

The previous prime is 209940047. The next prime is 209940083. The reversal of 209940073 is 370049902.

209940073 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 370049902 = 2 ⋅185024951.

It is a cyclic number.

It is not a de Polignac number, because 209940073 - 2⁵ = 209940041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209940083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14995713 + ... + 14995726.

It is an arithmetic number, because the mean of its divisors is an integer number (59982880).

Almost surely, 2^209940073 is an apocalyptic number.

It is an amenable number.

209940073 is a deficient number, since it is larger than the sum of its proper divisors (29991447).

209940073 is an equidigital number, since it uses as much as digits as its factorization.

209940073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29991446.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 209940073 is about 14489.3089207181. The cubic root of 209940073 is about 594.3356499908.

Adding to 209940073 its reverse (370049902), we get a palindrome (579989975).

The spelling of 209940073 in words is "two hundred nine million, nine hundred forty thousand, seventy-three".