209398643 has 4 divisors (see below), whose sum is σ = 209522880. Its totient is φ = 209274408.

The previous prime is 209398633. The next prime is 209398649. The reversal of 209398643 is 346893902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 209398643 - 2¹⁴ = 209382259 is a prime.

It is a super-4 number, since 4×209398643⁴ (a number of 34 digits) contains 4444 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209398594 and 209398603.

It is not an unprimeable number, because it can be changed into a prime (209398649) 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, 59555 + ... + 62972.

It is an arithmetic number, because the mean of its divisors is an integer number (52380720).

Almost surely, 2^209398643 is an apocalyptic number.

209398643 is a deficient number, since it is larger than the sum of its proper divisors (124237).

209398643 is a wasteful number, since it uses less digits than its factorization.

209398643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124236.

The product of its (nonzero) digits is 279936, while the sum is 44.

The square root of 209398643 is about 14470.6130830729. The cubic root of 209398643 is about 593.8242847335.

The spelling of 209398643 in words is "two hundred nine million, three hundred ninety-eight thousand, six hundred forty-three".