18013381 has 2 divisors, whose sum is σ = 18013382. Its totient is φ = 18013380.

The previous prime is 18013367. The next prime is 18013409. The reversal of 18013381 is 18331081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17564481 + 448900 = 4191^2 + 670^2 .

It is a cyclic number.

It is not a de Polignac number, because 18013381 - 2⁷ = 18013253 is a prime.

It is a super-2 number, since 2×18013381² = 648963790102322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18013181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9006690 + 9006691.

It is an arithmetic number, because the mean of its divisors is an integer number (9006691).

Almost surely, 2^18013381 is an apocalyptic number.

It is an amenable number.

18013381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18013381 is an equidigital number, since it uses as much as digits as its factorization.

18013381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 18013381 is about 4244.2173601266. The cubic root of 18013381 is about 262.1390643365.

The spelling of 18013381 in words is "eighteen million, thirteen thousand, three hundred eighty-one".