18978144 has 24 divisors (see below), whose sum is σ = 49817880. Its totient is φ = 6326016.

The previous prime is 18978119. The next prime is 18978161. The reversal of 18978144 is 44187981.

It is a tau number, because it is divible by the number of its divisors (24).

It is a junction number, because it is equal to n+sod(n) for n = 18978096 and 18978105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98749 + ... + 98940.

It is an arithmetic number, because the mean of its divisors is an integer number (2075745).

Almost surely, 2^18978144 is an apocalyptic number.

It is an amenable number.

18978144 is an abundant number, since it is smaller than the sum of its proper divisors (30839736).

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

18978144 is a wasteful number, since it uses less digits than its factorization.

18978144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197702 (or 197694 counting only the distinct ones).

The product of its digits is 64512, while the sum is 42.

The square root of 18978144 is about 4356.3911670097. The cubic root of 18978144 is about 266.7378087966.

The spelling of 18978144 in words is "eighteen million, nine hundred seventy-eight thousand, one hundred forty-four".