18121380 has 48 divisors (see below), whose sum is σ = 51105600. Its totient is φ = 4797568.

The previous prime is 18121351. The next prime is 18121387. The reversal of 18121380 is 8312181.

It is a self number, because there is not a number n which added to its sum of digits gives 18121380.

It is not an unprimeable number, because it can be changed into a prime (18121387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7927 + ... + 9953.

It is an arithmetic number, because the mean of its divisors is an integer number (1064700).

Almost surely, 2^18121380 is an apocalyptic number.

18121380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18121380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25552800).

18121380 is an abundant number, since it is smaller than the sum of its proper divisors (32984220).

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

18121380 is a wasteful number, since it uses less digits than its factorization.

18121380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2188 (or 2186 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 24.

The square root of 18121380 is about 4256.9214228125. The cubic root of 18121380 is about 262.6619046551.

The spelling of 18121380 in words is "eighteen million, one hundred twenty-one thousand, three hundred eighty".