18681408 has 112 divisors (see below), whose sum is σ = 57912000. Its totient is φ = 5889024.

The previous prime is 18681373. The next prime is 18681431. The reversal of 18681408 is 80418681.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32548 + ... + 33116.

Almost surely, 2^18681408 is an apocalyptic number.

18681408 is a gapful number since it is divisible by the number (18) 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 18681408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28956000).

18681408 is an abundant number, since it is smaller than the sum of its proper divisors (39230592).

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

18681408 is a wasteful number, since it uses less digits than its factorization.

18681408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609 (or 593 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 18681408 is about 4322.1994400999. The cubic root of 18681408 is about 265.3402914488.

The spelling of 18681408 in words is "eighteen million, six hundred eighty-one thousand, four hundred eight".