18440400 has 180 divisors, whose sum is σ = 65440256. Its totient is φ = 4435200.

The previous prime is 18440377. The next prime is 18440413. The reversal of 18440400 is 404481.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 145137 + ... + 145263.

Almost surely, 2^18440400 is an apocalyptic number.

18440400 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 18440400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32720128).

18440400 is an abundant number, since it is smaller than the sum of its proper divisors (46999856).

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

18440400 is a wasteful number, since it uses less digits than its factorization.

18440400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 18440400 is about 4294.2286851075. The cubic root of 18440400 is about 264.1943014054.

Adding to 18440400 its reverse (404481), we get a palindrome (18844881).

The spelling of 18440400 in words is "eighteen million, four hundred forty thousand, four hundred".