18484381 has 2 divisors, whose sum is σ = 18484382. Its totient is φ = 18484380.

The previous prime is 18484379. The next prime is 18484391. The reversal of 18484381 is 18348481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15280281 + 3204100 = 3909^2 + 1790^2 .

It is an emirp because it is prime and its reverse (18348481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18484381 - 2¹ = 18484379 is a prime.

It is a super-2 number, since 2×18484381² = 683344681906322, which contains 22 as substring.

Together with 18484379, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18484381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18484351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9242190 + 9242191.

It is an arithmetic number, because the mean of its divisors is an integer number (9242191).

Almost surely, 2^18484381 is an apocalyptic number.

It is an amenable number.

18484381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18484381 is an equidigital number, since it uses as much as digits as its factorization.

18484381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24576, while the sum is 37.

The square root of 18484381 is about 4299.3465782605. The cubic root of 18484381 is about 264.4041721987.

The spelling of 18484381 in words is "eighteen million, four hundred eighty-four thousand, three hundred eighty-one".