209009779899 has 4 divisors (see below), whose sum is σ = 278679706536. Its totient is φ = 139339853264.

The previous prime is 209009779873. The next prime is 209009779921. The reversal of 209009779899 is 998977900902.

209009779899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 209009779899 - 2⁹ = 209009779387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (209009779829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34834963314 + ... + 34834963319.

It is an arithmetic number, because the mean of its divisors is an integer number (69669926634).

Almost surely, 2^209009779899 is an apocalyptic number.

209009779899 is a deficient number, since it is larger than the sum of its proper divisors (69669926637).

209009779899 is an equidigital number, since it uses as much as digits as its factorization.

209009779899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69669926636.

The product of its (nonzero) digits is 46294416, while the sum is 69.

The spelling of 209009779899 in words is "two hundred nine billion, nine million, seven hundred seventy-nine thousand, eight hundred ninety-nine".