218342765509 has 4 divisors (see below), whose sum is σ = 238192107840. Its totient is φ = 198493423180.

The previous prime is 218342765489. The next prime is 218342765569. The reversal of 218342765509 is 905567243812.

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 a cyclic number.

It is not a de Polignac number, because 218342765509 - 2⁵ = 218342765477 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 (218342765569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9924671149 + ... + 9924671170.

It is an arithmetic number, because the mean of its divisors is an integer number (59548026960).

It is a 1-persistent number, because it is pandigital, but 2⋅218342765509 = 436685531018 is not.

Almost surely, 2^218342765509 is an apocalyptic number.

It is an amenable number.

218342765509 is a deficient number, since it is larger than the sum of its proper divisors (19849342331).

218342765509 is a wasteful number, since it uses less digits than its factorization.

218342765509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19849342330.

The product of its (nonzero) digits is 3628800, while the sum is 52.

The spelling of 218342765509 in words is "two hundred eighteen billion, three hundred forty-two million, seven hundred sixty-five thousand, five hundred nine".