18988440 has 64 divisors (see below), whose sum is σ = 57715200. Its totient is φ = 4996992.

The previous prime is 18988421. The next prime is 18988471. The reversal of 18988440 is 4488981.

It is a junction number, because it is equal to n+sod(n) for n = 18988392 and 18988401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8479 + ... + 10481.

It is an arithmetic number, because the mean of its divisors is an integer number (901800).

Almost surely, 2^18988440 is an apocalyptic number.

18988440 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 18988440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28857600).

18988440 is an abundant number, since it is smaller than the sum of its proper divisors (38726760).

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

18988440 is a wasteful number, since it uses less digits than its factorization.

18988440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2096 (or 2092 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 42.

The square root of 18988440 is about 4357.5727188425. The cubic root of 18988440 is about 266.7860368352.

The spelling of 18988440 in words is "eighteen million, nine hundred eighty-eight thousand, four hundred forty".