218780819 has 2 divisors, whose sum is σ = 218780820. Its totient is φ = 218780818.

The previous prime is 218780813. The next prime is 218780833. The reversal of 218780819 is 918087812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 218780819 - 2¹⁶ = 218715283 is a prime.

It is a super-2 number, since 2×218780819² = 95730093524621522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 218780819.

It is not a weakly prime, because it can be changed into another prime (218780813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109390409 + 109390410.

It is an arithmetic number, because the mean of its divisors is an integer number (109390410).

Almost surely, 2^218780819 is an apocalyptic number.

218780819 is a deficient number, since it is larger than the sum of its proper divisors (1).

218780819 is an equidigital number, since it uses as much as digits as its factorization.

218780819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64512, while the sum is 44.

The square root of 218780819 is about 14791.2412934142. The cubic root of 218780819 is about 602.5638611625.

The spelling of 218780819 in words is "two hundred eighteen million, seven hundred eighty thousand, eight hundred nineteen".