218710372818809 has 4 divisors (see below), whose sum is σ = 218711020809204. Its totient is φ = 218709724828416.

The previous prime is 218710372818733. The next prime is 218710372818827. The reversal of 218710372818809 is 908818273017812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64578147818809 + 154132225000000 = 8036053^2 + 12415000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218710372818809 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (218710372818209) 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, 323488652 + ... + 324164045.

It is an arithmetic number, because the mean of its divisors is an integer number (54677755202301).

Almost surely, 2^{218710372818809} is an apocalyptic number.

It is an amenable number.

218710372818809 is a deficient number, since it is larger than the sum of its proper divisors (647990395).

218710372818809 is an equidigital number, since it uses as much as digits as its factorization.

218710372818809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647990394.

The product of its (nonzero) digits is 21676032, while the sum is 65.

The spelling of 218710372818809 in words is "two hundred eighteen trillion, seven hundred ten billion, three hundred seventy-two million, eight hundred eighteen thousand, eight hundred nine".