18281312 has 72 divisors (see below), whose sum is σ = 42661080. Its totient is φ = 7687680.

The previous prime is 18281309. The next prime is 18281353. The reversal of 18281312 is 21318281.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139487 + ... + 139617.

It is an arithmetic number, because the mean of its divisors is an integer number (592515).

Almost surely, 2^18281312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18281312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21330540).

18281312 is an abundant number, since it is smaller than the sum of its proper divisors (24379768).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18281312 is a wasteful number, since it uses less digits than its factorization.

18281312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 229 counting only the distinct ones).

The product of its digits is 768, while the sum is 26.

The square root of 18281312 is about 4275.6650944619. The cubic root of 18281312 is about 263.4323585629.

Adding to 18281312 its reverse (21318281), we get a palindrome (39599593).

The spelling of 18281312 in words is "eighteen million, two hundred eighty-one thousand, three hundred twelve".