18413581 has 2 divisors, whose sum is σ = 18413582. Its totient is φ = 18413580.

The previous prime is 18413561. The next prime is 18413609. The reversal of 18413581 is 18531481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18412681 + 900 = 4291^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 18413581 - 2⁷ = 18413453 is a prime.

It is a super-2 number, since 2×18413581² = 678119930487122, 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 (18413561) 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, 9206790 + 9206791.

It is an arithmetic number, because the mean of its divisors is an integer number (9206791).

Almost surely, 2^18413581 is an apocalyptic number.

It is an amenable number.

18413581 is a deficient number, since it is larger than the sum of its proper divisors (1).

18413581 is an equidigital number, since it uses as much as digits as its factorization.

18413581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 31.

The square root of 18413581 is about 4291.1048693780. The cubic root of 18413581 is about 264.0661612951.

The spelling of 18413581 in words is "eighteen million, four hundred thirteen thousand, five hundred eighty-one".