18978880 has 56 divisors (see below), whose sum is σ = 45646848. Its totient is φ = 7515648.

The previous prime is 18978871. The next prime is 18978893. The reversal of 18978880 is 8887981.

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, 40407 + ... + 40873.

Almost surely, 2^18978880 is an apocalyptic number.

18978880 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 18978880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22823424).

18978880 is an abundant number, since it is smaller than the sum of its proper divisors (26667968).

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

18978880 is a wasteful number, since it uses less digits than its factorization.

18978880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611 (or 601 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 49.

The square root of 18978880 is about 4356.4756397804. The cubic root of 18978880 is about 266.7412569119.

The spelling of 18978880 in words is "eighteen million, nine hundred seventy-eight thousand, eight hundred eighty".