18909888 has 56 divisors (see below), whose sum is σ = 50444400. Its totient is φ = 6251520.

The previous prime is 18909853. The next prime is 18909901. The reversal of 18909888 is 88890981.

It is a self number, because there is not a number n which added to its sum of digits gives 18909888.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28278 + ... + 28938.

Almost surely, 2^18909888 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18909888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25222200).

18909888 is an abundant number, since it is smaller than the sum of its proper divisors (31534512).

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

18909888 is a wasteful number, since it uses less digits than its factorization.

18909888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825 (or 815 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 51.

The square root of 18909888 is about 4348.5501031953. The cubic root of 18909888 is about 266.4176453065.

The spelling of 18909888 in words is "eighteen million, nine hundred nine thousand, eight hundred eighty-eight".