218090381 has 2 divisors, whose sum is σ = 218090382. Its totient is φ = 218090380.

The previous prime is 218090377. The next prime is 218090407. The reversal of 218090381 is 183090812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214886281 + 3204100 = 14659^2 + 1790^2 .

It is a cyclic number.

It is not a de Polignac number, because 218090381 - 2² = 218090377 is a prime.

It is a super-2 number, since 2×218090381² = 95126828569450322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218090581) 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, 109045190 + 109045191.

It is an arithmetic number, because the mean of its divisors is an integer number (109045191).

Almost surely, 2^218090381 is an apocalyptic number.

It is an amenable number.

218090381 is a deficient number, since it is larger than the sum of its proper divisors (1).

218090381 is an equidigital number, since it uses as much as digits as its factorization.

218090381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 218090381 is about 14767.8834299300. The cubic root of 218090381 is about 601.9293274726.

The spelling of 218090381 in words is "two hundred eighteen million, ninety thousand, three hundred eighty-one".