18681378 has 16 divisors (see below), whose sum is σ = 37889856. Its totient is φ = 6139280.

The previous prime is 18681373. The next prime is 18681431. The reversal of 18681378 is 87318681.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18681371) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21501 + ... + 22352.

It is an arithmetic number, because the mean of its divisors is an integer number (2368116).

Almost surely, 2^18681378 is an apocalyptic number.

18681378 is an abundant number, since it is smaller than the sum of its proper divisors (19208478).

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

18681378 is a wasteful number, since it uses less digits than its factorization.

18681378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43929.

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

The square root of 18681378 is about 4322.1959696432. The cubic root of 18681378 is about 265.3401494143.

The spelling of 18681378 in words is "eighteen million, six hundred eighty-one thousand, three hundred seventy-eight".