218057321 has 2 divisors, whose sum is σ = 218057322. Its totient is φ = 218057320.

The previous prime is 218057309. The next prime is 218057327. The reversal of 218057321 is 123750812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135955600 + 82101721 = 11660^2 + 9061^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218057321 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218057327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109028660 + 109028661.

It is an arithmetic number, because the mean of its divisors is an integer number (109028661).

Almost surely, 2^218057321 is an apocalyptic number.

It is an amenable number.

218057321 is a deficient number, since it is larger than the sum of its proper divisors (1).

218057321 is an equidigital number, since it uses as much as digits as its factorization.

218057321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 218057321 is about 14766.7640666464. The cubic root of 218057321 is about 601.8989107418.

The spelling of 218057321 in words is "two hundred eighteen million, fifty-seven thousand, three hundred twenty-one".