18688500 has 72 divisors (see below), whose sum is σ = 58970184. Its totient is φ = 4982400.

The previous prime is 18688451. The next prime is 18688519. The reversal of 18688500 is 588681.

It can be written as a sum of positive squares in 4 ways, for example, as 5116644 + 13571856 = 2262^2 + 3684^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2424 + ... + 6576.

Almost surely, 2^18688500 is an apocalyptic number.

18688500 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 18688500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29485092).

18688500 is an abundant number, since it is smaller than the sum of its proper divisors (40281684).

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

18688500 is a wasteful number, since it uses less digits than its factorization.

18688500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4178 (or 4163 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The square root of 18688500 is about 4323.0197778867. The cubic root of 18688500 is about 265.3738641372.

The spelling of 18688500 in words is "eighteen million, six hundred eighty-eight thousand, five hundred".