205020340509 has 8 divisors (see below), whose sum is σ = 273389470912. Its totient is φ = 136665718560.

The previous prime is 205020340489. The next prime is 205020340537. The reversal of 205020340509 is 905043020502.

205020340509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 205020340509 - 2¹⁵ = 205020307741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205020340559) 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 7 ways as a sum of consecutive naturals, for example, 3594097 + ... + 3650694.

It is an arithmetic number, because the mean of its divisors is an integer number (34173683864).

Almost surely, 2^205020340509 is an apocalyptic number.

It is an amenable number.

205020340509 is a deficient number, since it is larger than the sum of its proper divisors (68369130403).

205020340509 is an equidigital number, since it uses as much as digits as its factorization.

205020340509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7254227.

The product of its (nonzero) digits is 10800, while the sum is 30.

The spelling of 205020340509 in words is "two hundred five billion, twenty million, three hundred forty thousand, five hundred nine".