381218393 has 2 divisors, whose sum is σ = 381218394. Its totient is φ = 381218392.

The previous prime is 381218359. The next prime is 381218401. The reversal of 381218393 is 393812183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211906249 + 169312144 = 14557^2 + 13012^2 .

It is a cyclic number.

It is not a de Polignac number, because 381218393 - 2⁶ = 381218329 is a prime.

It is a super-3 number, since 3×381218393³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (381218303) 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, 190609196 + 190609197.

It is an arithmetic number, because the mean of its divisors is an integer number (190609197).

Almost surely, 2^381218393 is an apocalyptic number.

It is an amenable number.

381218393 is a deficient number, since it is larger than the sum of its proper divisors (1).

381218393 is an equidigital number, since it uses as much as digits as its factorization.

381218393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 381218393 is about 19524.8148006582. The cubic root of 381218393 is about 725.0889422392.

The spelling of 381218393 in words is "three hundred eighty-one million, two hundred eighteen thousand, three hundred ninety-three".