218345861 has 2 divisors, whose sum is σ = 218345862. Its totient is φ = 218345860.

The previous prime is 218345837. The next prime is 218345863. The reversal of 218345861 is 168543812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142324900 + 76020961 = 11930^2 + 8719^2 .

It is a cyclic number.

It is not a de Polignac number, because 218345861 - 2⁶ = 218345797 is a prime.

Together with 218345863, 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 (218345863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109172930 + 109172931.

It is an arithmetic number, because the mean of its divisors is an integer number (109172931).

Almost surely, 2^218345861 is an apocalyptic number.

It is an amenable number.

218345861 is a deficient number, since it is larger than the sum of its proper divisors (1).

218345861 is an equidigital number, since it uses as much as digits as its factorization.

218345861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46080, while the sum is 38.

The square root of 218345861 is about 14776.5307498073. The cubic root of 218345861 is about 602.1642773047.

The spelling of 218345861 in words is "two hundred eighteen million, three hundred forty-five thousand, eight hundred sixty-one".