18717481 has 2 divisors, whose sum is σ = 18717482. Its totient is φ = 18717480.

The previous prime is 18717473. The next prime is 18717509. The reversal of 18717481 is 18471781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12138256 + 6579225 = 3484^2 + 2565^2 .

It is a cyclic number.

It is not a de Polignac number, because 18717481 - 2³ = 18717473 is a prime.

It is a super-2 number, since 2×18717481² = 700688189970722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18717481.

It is not a weakly prime, because it can be changed into another prime (18717581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9358740 + 9358741.

It is an arithmetic number, because the mean of its divisors is an integer number (9358741).

Almost surely, 2^18717481 is an apocalyptic number.

It is an amenable number.

18717481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18717481 is an equidigital number, since it uses as much as digits as its factorization.

18717481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12544, while the sum is 37.

The square root of 18717481 is about 4326.3704187228. The cubic root of 18717481 is about 265.5109685579.

The spelling of 18717481 in words is "eighteen million, seven hundred seventeen thousand, four hundred eighty-one".