218728049 has 2 divisors, whose sum is σ = 218728050. Its totient is φ = 218728048.

The previous prime is 218728007. The next prime is 218728117. The reversal of 218728049 is 940827812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217120225 + 1607824 = 14735^2 + 1268^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218728049 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 218727997 and 218728015.

It is not a weakly prime, because it can be changed into another prime (218721049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109364024 + 109364025.

It is an arithmetic number, because the mean of its divisors is an integer number (109364025).

Almost surely, 2^218728049 is an apocalyptic number.

It is an amenable number.

218728049 is a deficient number, since it is larger than the sum of its proper divisors (1).

218728049 is an equidigital number, since it uses as much as digits as its factorization.

218728049 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 41.

The square root of 218728049 is about 14789.4573598898. The cubic root of 218728049 is about 602.5154110714.

The spelling of 218728049 in words is "two hundred eighteen million, seven hundred twenty-eight thousand, forty-nine".