18488381 has 2 divisors, whose sum is σ = 18488382. Its totient is φ = 18488380.

The previous prime is 18488377. The next prime is 18488413. The reversal of 18488381 is 18388481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14182756 + 4305625 = 3766^2 + 2075^2 .

It is a cyclic number.

It is not a de Polignac number, because 18488381 - 2² = 18488377 is a prime.

It is a super-2 number, since 2×18488381² = 683640464002322, 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 (18488321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9244190 + 9244191.

It is an arithmetic number, because the mean of its divisors is an integer number (9244191).

Almost surely, 2^18488381 is an apocalyptic number.

It is an amenable number.

18488381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18488381 is an equidigital number, since it uses as much as digits as its factorization.

18488381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49152, while the sum is 41.

The square root of 18488381 is about 4299.8117400649. The cubic root of 18488381 is about 264.4232430818.

The spelling of 18488381 in words is "eighteen million, four hundred eighty-eight thousand, three hundred eighty-one".