18138880 has 72 divisors (see below), whose sum is σ = 44739072. Its totient is φ = 7041024.

The previous prime is 18138871. The next prime is 18138919. The reversal of 18138880 is 8883181.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47169 + ... + 47551.

It is an arithmetic number, because the mean of its divisors is an integer number (621376).

Almost surely, 2^18138880 is an apocalyptic number.

18138880 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 18138880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22369536).

18138880 is an abundant number, since it is smaller than the sum of its proper divisors (26600192).

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

18138880 is an equidigital number, since it uses as much as digits as its factorization.

18138880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 441 (or 427 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 37.

The square root of 18138880 is about 4258.9764028461. The cubic root of 18138880 is about 262.7464292051.

The spelling of 18138880 in words is "eighteen million, one hundred thirty-eight thousand, eight hundred eighty".