209397943 has 2 divisors, whose sum is σ = 209397944. Its totient is φ = 209397942.

The previous prime is 209397941. The next prime is 209397967. The reversal of 209397943 is 349793902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209397943 - 2¹ = 209397941 is a prime.

Together with 209397941, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 209397893 and 209397902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209397941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104698971 + 104698972.

It is an arithmetic number, because the mean of its divisors is an integer number (104698972).

Almost surely, 2^209397943 is an apocalyptic number.

209397943 is a deficient number, since it is larger than the sum of its proper divisors (1).

209397943 is an equidigital number, since it uses as much as digits as its factorization.

209397943 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 367416, while the sum is 46.

The square root of 209397943 is about 14470.5888961023. The cubic root of 209397943 is about 593.8236230331.

It can be divided in two parts, 20939 and 7943, that added together give a palindrome (28882).

The spelling of 209397943 in words is "two hundred nine million, three hundred ninety-seven thousand, nine hundred forty-three".