218961791 has 2 divisors, whose sum is σ = 218961792. Its totient is φ = 218961790.

The previous prime is 218961739. The next prime is 218961793. The reversal of 218961791 is 197169812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 218961791 - 2¹⁰ = 218960767 is a prime.

Together with 218961793, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218961793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109480895 + 109480896.

It is an arithmetic number, because the mean of its divisors is an integer number (109480896).

Almost surely, 2^218961791 is an apocalyptic number.

218961791 is a deficient number, since it is larger than the sum of its proper divisors (1).

218961791 is an equidigital number, since it uses as much as digits as its factorization.

218961791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 44.

The square root of 218961791 is about 14797.3575681606. The cubic root of 218961791 is about 602.7299591078.

The spelling of 218961791 in words is "two hundred eighteen million, nine hundred sixty-one thousand, seven hundred ninety-one".