218102921 has 2 divisors, whose sum is σ = 218102922. Its totient is φ = 218102920.

The previous prime is 218102909. The next prime is 218102933. The reversal of 218102921 is 129201812.

It is a balanced prime because it is at equal distance from previous prime (218102909) and next prime (218102933).

It can be written as a sum of positive squares in only one way, i.e., 176358400 + 41744521 = 13280^2 + 6461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218102921 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218102971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109051460 + 109051461.

It is an arithmetic number, because the mean of its divisors is an integer number (109051461).

Almost surely, 2^218102921 is an apocalyptic number.

It is an amenable number.

218102921 is a deficient number, since it is larger than the sum of its proper divisors (1).

218102921 is an equidigital number, since it uses as much as digits as its factorization.

218102921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 218102921 is about 14768.3079938089. The cubic root of 218102921 is about 601.9408640491.

The spelling of 218102921 in words is "two hundred eighteen million, one hundred two thousand, nine hundred twenty-one".