18281313 has 6 divisors (see below), whose sum is σ = 26406354. Its totient is φ = 12187536.

The previous prime is 18281309. The next prime is 18281353. The reversal of 18281313 is 31318281.

It can be written as a sum of positive squares in only one way, i.e., 18249984 + 31329 = 4272^2 + 177^2 .

It is not a de Polignac number, because 18281313 - 2² = 18281309 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18281353) 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 in 5 ways as a sum of consecutive naturals, for example, 1015620 + ... + 1015637.

It is an arithmetic number, because the mean of its divisors is an integer number (4401059).

Almost surely, 2^18281313 is an apocalyptic number.

It is an amenable number.

18281313 is a deficient number, since it is larger than the sum of its proper divisors (8125041).

18281313 is a wasteful number, since it uses less digits than its factorization.

18281313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2031263 (or 2031260 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 18281313 is about 4275.6652114028. The cubic root of 18281313 is about 263.4323633662.

Adding to 18281313 its reverse (31318281), we get a palindrome (49599594).

The spelling of 18281313 in words is "eighteen million, two hundred eighty-one thousand, three hundred thirteen".