209644993489 has 2 divisors, whose sum is σ = 209644993490. Its totient is φ = 209644993488.

The previous prime is 209644993487. The next prime is 209644993501. The reversal of 209644993489 is 984399446902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123968776464 + 85676217025 = 352092^2 + 292705^2 .

It is a cyclic number.

It is not a de Polignac number, because 209644993489 - 2¹ = 209644993487 is a prime.

Together with 209644993487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (209644993487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104822496744 + 104822496745.

It is an arithmetic number, because the mean of its divisors is an integer number (104822496745).

Almost surely, 2^209644993489 is an apocalyptic number.

It is an amenable number.

209644993489 is a deficient number, since it is larger than the sum of its proper divisors (1).

209644993489 is an equidigital number, since it uses as much as digits as its factorization.

209644993489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120932352, while the sum is 67.

The spelling of 209644993489 in words is "two hundred nine billion, six hundred forty-four million, nine hundred ninety-three thousand, four hundred eighty-nine".