18381408 has 24 divisors (see below), whose sum is σ = 48251448. Its totient is φ = 6127104.

The previous prime is 18381397. The next prime is 18381457. The reversal of 18381408 is 80418381.

It is a happy number.

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

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, 95641 + ... + 95832.

It is an arithmetic number, because the mean of its divisors is an integer number (2010477).

Almost surely, 2^18381408 is an apocalyptic number.

It is an amenable number.

18381408 is an abundant number, since it is smaller than the sum of its proper divisors (29870040).

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

18381408 is a wasteful number, since it uses less digits than its factorization.

18381408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191486 (or 191478 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 18381408 is about 4287.3544290156. The cubic root of 18381408 is about 263.9122757203.

Adding to 18381408 its reverse (80418381), we get a palindrome (98799789).

The spelling of 18381408 in words is "eighteen million, three hundred eighty-one thousand, four hundred eight".