18138330 has 120 divisors (see below), whose sum is σ = 56858868. Its totient is φ = 4136832.

The previous prime is 18138247. The next prime is 18138343. The reversal of 18138330 is 3383181.

It can be written as a sum of positive squares in 2 ways, for example, as 17816841 + 321489 = 4221^2 + 567^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 18138294 and 18138303.

It is an unprimeable number.

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 59 ways as a sum of consecutive naturals, for example, 39462 + ... + 39918.

Almost surely, 2^18138330 is an apocalyptic number.

18138330 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18138330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28429434).

18138330 is an abundant number, since it is smaller than the sum of its proper divisors (38720538).

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

18138330 is a wasteful number, since it uses less digits than its factorization.

18138330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 490 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 18138330 is about 4258.9118328512. The cubic root of 18138330 is about 262.7437735469.

The spelling of 18138330 in words is "eighteen million, one hundred thirty-eight thousand, three hundred thirty".