18383381 has 2 divisors, whose sum is σ = 18383382. Its totient is φ = 18383380.

The previous prime is 18383363. The next prime is 18383389. The reversal of 18383381 is 18338381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15476356 + 2907025 = 3934^2 + 1705^2 .

It is an emirp because it is prime and its reverse (18338381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18383381 - 2¹⁸ = 18121237 is a prime.

It is a super-2 number, since 2×18383381² = 675897393982322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18383389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9191690 + 9191691.

It is an arithmetic number, because the mean of its divisors is an integer number (9191691).

Almost surely, 2^18383381 is an apocalyptic number.

It is an amenable number.

18383381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18383381 is an equidigital number, since it uses as much as digits as its factorization.

18383381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 35.

The square root of 18383381 is about 4287.5845181174. The cubic root of 18383381 is about 263.9217178749.

The spelling of 18383381 in words is "eighteen million, three hundred eighty-three thousand, three hundred eighty-one".