218388234221 has 2 divisors, whose sum is σ = 218388234222. Its totient is φ = 218388234220.

The previous prime is 218388234137. The next prime is 218388234299. The reversal of 218388234221 is 122432883812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211311218596 + 7077015625 = 459686^2 + 84125^2 .

It is a cyclic number.

It is not a de Polignac number, because 218388234221 - 2³⁴ = 201208365037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218388284221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109194117110 + 109194117111.

It is an arithmetic number, because the mean of its divisors is an integer number (109194117111).

Almost surely, 2^218388234221 is an apocalyptic number.

It is an amenable number.

218388234221 is a deficient number, since it is larger than the sum of its proper divisors (1).

218388234221 is an equidigital number, since it uses as much as digits as its factorization.

218388234221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 294912, while the sum is 44.

The spelling of 218388234221 in words is "two hundred eighteen billion, three hundred eighty-eight million, two hundred thirty-four thousand, two hundred twenty-one".