218839979 has 2 divisors, whose sum is σ = 218839980. Its totient is φ = 218839978.

The previous prime is 218839961. The next prime is 218839987. The reversal of 218839979 is 979938812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 218839979 - 2¹⁶ = 218774443 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218830979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109419989 + 109419990.

It is an arithmetic number, because the mean of its divisors is an integer number (109419990).

Almost surely, 2^218839979 is an apocalyptic number.

218839979 is a deficient number, since it is larger than the sum of its proper divisors (1).

218839979 is an equidigital number, since it uses as much as digits as its factorization.

218839979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1959552, while the sum is 56.

The square root of 218839979 is about 14793.2409903983. The cubic root of 218839979 is about 602.6181688870.

The spelling of 218839979 in words is "two hundred eighteen million, eight hundred thirty-nine thousand, nine hundred seventy-nine".