18987885 has 64 divisors (see below), whose sum is σ = 39260160. Its totient is φ = 8527680.

The previous prime is 18987877. The next prime is 18987889. The reversal of 18987885 is 58878981.

It is not a de Polignac number, because 18987885 - 2³ = 18987877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18987889) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 66954 + ... + 67236.

It is an arithmetic number, because the mean of its divisors is an integer number (613440).

Almost surely, 2^18987885 is an apocalyptic number.

18987885 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18987885 is an abundant number, since it is smaller than the sum of its proper divisors (20272275).

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

18987885 is a wasteful number, since it uses less digits than its factorization.

18987885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 369 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 54.

The square root of 18987885 is about 4357.5090361352. The cubic root of 18987885 is about 266.7834375749.

The spelling of 18987885 in words is "eighteen million, nine hundred eighty-seven thousand, eight hundred eighty-five".