218198381 has 2 divisors, whose sum is σ = 218198382. Its totient is φ = 218198380.

The previous prime is 218198371. The next prime is 218198399. The reversal of 218198381 is 183891812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214622500 + 3575881 = 14650^2 + 1891^2 .

It is a cyclic number.

It is not a de Polignac number, because 218198381 - 2⁶ = 218198317 is a prime.

It is a super-2 number, since 2×218198381² = 95221066942042322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218198311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109099190 + 109099191.

It is an arithmetic number, because the mean of its divisors is an integer number (109099191).

Almost surely, 2^218198381 is an apocalyptic number.

It is an amenable number.

218198381 is a deficient number, since it is larger than the sum of its proper divisors (1).

218198381 is an equidigital number, since it uses as much as digits as its factorization.

218198381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 41.

The square root of 218198381 is about 14771.5395609259. The cubic root of 218198381 is about 602.0286710553.

The spelling of 218198381 in words is "two hundred eighteen million, one hundred ninety-eight thousand, three hundred eighty-one".