18401840 has 80 divisors (see below), whose sum is σ = 45586368. Its totient is φ = 6893568.

The previous prime is 18401833. The next prime is 18401843. The reversal of 18401840 is 4810481.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (18401843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134252 + ... + 134388.

Almost surely, 2^18401840 is an apocalyptic number.

18401840 is a gapful number since it is divisible by the number (10) 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 18401840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22793184).

18401840 is an abundant number, since it is smaller than the sum of its proper divisors (27184528).

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

18401840 is a wasteful number, since it uses less digits than its factorization.

18401840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 18401840 is about 4289.7365886497. The cubic root of 18401840 is about 264.0100241067.

The spelling of 18401840 in words is "eighteen million, four hundred one thousand, eight hundred forty".