18009312 has 24 divisors (see below), whose sum is σ = 47274696. Its totient is φ = 6003072.

The previous prime is 18009289. The next prime is 18009323. The reversal of 18009312 is 21390081.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93703 + ... + 93894.

It is an arithmetic number, because the mean of its divisors is an integer number (1969779).

Almost surely, 2^18009312 is an apocalyptic number.

18009312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18009312 is an abundant number, since it is smaller than the sum of its proper divisors (29265384).

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

18009312 is a wasteful number, since it uses less digits than its factorization.

18009312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187610 (or 187602 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 18009312 is about 4243.7379749461. The cubic root of 18009312 is about 262.1193248592.

Adding to 18009312 its reverse (21390081), we get a palindrome (39399393).

The spelling of 18009312 in words is "eighteen million, nine thousand, three hundred twelve".