209365243 has 4 divisors (see below), whose sum is σ = 209557888. Its totient is φ = 209172600.

The previous prime is 209365231. The next prime is 209365249. The reversal of 209365243 is 342563902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 342563902 = 2 ⋅171281951.

It is a cyclic number.

It is not a de Polignac number, because 209365243 - 2¹⁷ = 209234171 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209365199 and 209365208.

It is not an unprimeable number, because it can be changed into a prime (209365249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94683 + ... + 96868.

It is an arithmetic number, because the mean of its divisors is an integer number (52389472).

Almost surely, 2^209365243 is an apocalyptic number.

209365243 is a deficient number, since it is larger than the sum of its proper divisors (192645).

209365243 is a wasteful number, since it uses less digits than its factorization.

209365243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192644.

The product of its (nonzero) digits is 38880, while the sum is 34.

The square root of 209365243 is about 14469.4589739907. The cubic root of 209365243 is about 593.7927105306.

The spelling of 209365243 in words is "two hundred nine million, three hundred sixty-five thousand, two hundred forty-three".