218429666509 has 2 divisors, whose sum is σ = 218429666510. Its totient is φ = 218429666508.

The previous prime is 218429666471. The next prime is 218429666531. The reversal of 218429666509 is 905666924812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 167420088900 + 51009577609 = 409170^2 + 225853^2 .

It is a cyclic number.

It is not a de Polignac number, because 218429666509 - 2¹¹ = 218429664461 is a prime.

It is a super-2 number, since 2×218429666509² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218429666599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109214833254 + 109214833255.

It is an arithmetic number, because the mean of its divisors is an integer number (109214833255).

Almost surely, 2^218429666509 is an apocalyptic number.

It is an amenable number.

218429666509 is a deficient number, since it is larger than the sum of its proper divisors (1).

218429666509 is an equidigital number, since it uses as much as digits as its factorization.

218429666509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11197440, while the sum is 58.

The spelling of 218429666509 in words is "two hundred eighteen billion, four hundred twenty-nine million, six hundred sixty-six thousand, five hundred nine".