218720819 has 2 divisors, whose sum is σ = 218720820. Its totient is φ = 218720818.

The previous prime is 218720791. The next prime is 218720839. The reversal of 218720819 is 918027812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 218720819 - 2²⁰ = 217672243 is a prime.

It is a super-2 number, since 2×218720819² = 95677593328061522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218720839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109360409 + 109360410.

It is an arithmetic number, because the mean of its divisors is an integer number (109360410).

Almost surely, 2^218720819 is an apocalyptic number.

218720819 is a deficient number, since it is larger than the sum of its proper divisors (1).

218720819 is an equidigital number, since it uses as much as digits as its factorization.

218720819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 218720819 is about 14789.2129269951. The cubic root of 218720819 is about 602.5087723337.

The spelling of 218720819 in words is "two hundred eighteen million, seven hundred twenty thousand, eight hundred nineteen".