218999999 has 2 divisors, whose sum is σ = 219000000. Its totient is φ = 218999998.

The previous prime is 218999953. The next prime is 219000011. The reversal of 218999999 is 999999812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218999999 is a prime.

It is a Sophie Germain prime.

218999999 is a modest number, since divided by 99999 gives 2189 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218399999) 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, 109499999 + 109500000.

It is an arithmetic number, because the mean of its divisors is an integer number (109500000).

Almost surely, 2^218999999 is an apocalyptic number.

218999999 is a deficient number, since it is larger than the sum of its proper divisors (1).

218999999 is an equidigital number, since it uses as much as digits as its factorization.

218999999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8503056, while the sum is 65.

The square root of 218999999 is about 14798.6485531619. The cubic root of 218999999 is about 602.7650150975.

The spelling of 218999999 in words is "two hundred eighteen million, nine hundred ninety-nine thousand, nine hundred ninety-nine".