18129840 has 40 divisors (see below), whose sum is σ = 56203248. Its totient is φ = 4834560.

The previous prime is 18129791. The next prime is 18129847. The reversal of 18129840 is 4892181.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (18129847) 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, 37531 + ... + 38010.

Almost surely, 2^18129840 is an apocalyptic number.

18129840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18129840 is an abundant number, since it is smaller than the sum of its proper divisors (38073408).

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

18129840 is a wasteful number, since it uses less digits than its factorization.

18129840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75557 (or 75551 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 18129840 is about 4257.9149827116. The cubic root of 18129840 is about 262.7027730291.

The spelling of 18129840 in words is "eighteen million, one hundred twenty-nine thousand, eight hundred forty".