209401243 has 2 divisors, whose sum is σ = 209401244. Its totient is φ = 209401242.

The previous prime is 209401229. The next prime is 209401259. The reversal of 209401243 is 342104902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209401243 - 2⁹ = 209400731 is a prime.

It is equal to p_11570191 and since 209401243 and 11570191 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (209401043) 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 as a sum of consecutive naturals, namely, 104700621 + 104700622.

It is an arithmetic number, because the mean of its divisors is an integer number (104700622).

Almost surely, 2^209401243 is an apocalyptic number.

209401243 is a deficient number, since it is larger than the sum of its proper divisors (1).

209401243 is an equidigital number, since it uses as much as digits as its factorization.

209401243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 209401243 is about 14470.7029200381. The cubic root of 209401243 is about 593.8267424647.

The spelling of 209401243 in words is "two hundred nine million, four hundred one thousand, two hundred forty-three".