18688140 has 72 divisors (see below), whose sum is σ = 57919680. Its totient is φ = 4877472.

The previous prime is 18688139. The next prime is 18688157. The reversal of 18688140 is 4188681.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18688095 and 18688104.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 397597 + ... + 397643.

It is an arithmetic number, because the mean of its divisors is an integer number (804440).

Almost surely, 2^18688140 is an apocalyptic number.

18688140 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 18688140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28959840).

18688140 is an abundant number, since it is smaller than the sum of its proper divisors (39231540).

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

18688140 is an equidigital number, since it uses as much as digits as its factorization.

18688140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 18688140 is about 4322.9781401252. The cubic root of 18688140 is about 265.3721601445.

The spelling of 18688140 in words is "eighteen million, six hundred eighty-eight thousand, one hundred forty".