18481657 has 4 divisors (see below), whose sum is σ = 18506340. Its totient is φ = 18456976.

The previous prime is 18481649. The next prime is 18481663. The reversal of 18481657 is 75618481.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1142761 + 17338896 = 1069^2 + 4164^2 .

It is a cyclic number.

It is not a de Polignac number, because 18481657 - 2³ = 18481649 is a prime.

It is a super-4 number, since 4×18481657⁴ (a number of 30 digits) contains 4444 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18481637) 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 in 3 ways as a sum of consecutive naturals, for example, 11182 + ... + 12727.

It is an arithmetic number, because the mean of its divisors is an integer number (4626585).

Almost surely, 2^18481657 is an apocalyptic number.

It is an amenable number.

18481657 is a deficient number, since it is larger than the sum of its proper divisors (24683).

18481657 is an equidigital number, since it uses as much as digits as its factorization.

18481657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24682.

The product of its digits is 53760, while the sum is 40.

The square root of 18481657 is about 4299.0297742630. The cubic root of 18481657 is about 264.3911833525.

The spelling of 18481657 in words is "eighteen million, four hundred eighty-one thousand, six hundred fifty-seven".