209545643361 has 4 divisors (see below), whose sum is σ = 279394191152. Its totient is φ = 139697095572.

The previous prime is 209545643339. The next prime is 209545643369. The reversal of 209545643361 is 163346545902.

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.

It is not a de Polignac number, because 209545643361 - 2⁶ = 209545643297 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 209545643361.

It is not an unprimeable number, because it can be changed into a prime (209545643369) 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, 34924273891 + ... + 34924273896.

It is an arithmetic number, because the mean of its divisors is an integer number (69848547788).

Almost surely, 2^209545643361 is an apocalyptic number.

It is an amenable number.

209545643361 is a deficient number, since it is larger than the sum of its proper divisors (69848547791).

209545643361 is an equidigital number, since it uses as much as digits as its factorization.

209545643361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69848547790.

The product of its (nonzero) digits is 2332800, while the sum is 48.

The spelling of 209545643361 in words is "two hundred nine billion, five hundred forty-five million, six hundred forty-three thousand, three hundred sixty-one".