18403840 has 160 divisors (see below), whose sum is σ = 54996480. Its totient is φ = 5750784.

The previous prime is 18403831. The next prime is 18403849. The reversal of 18403840 is 4830481.

It is an interprime number because it is at equal distance from previous prime (18403831) and next prime (18403849).

It is a tau number, because it is divible by the number of its divisors (160).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 18403799 and 18403808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18403849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 232921 + ... + 232999.

It is an arithmetic number, because the mean of its divisors is an integer number (343728).

Almost surely, 2^18403840 is an apocalyptic number.

18403840 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 18403840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27498240).

18403840 is an abundant number, since it is smaller than the sum of its proper divisors (36592640).

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

18403840 is an equidigital number, since it uses as much as digits as its factorization.

18403840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 106 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 18403840 is about 4289.9696968627. The cubic root of 18403840 is about 264.0195883843.

The spelling of 18403840 in words is "eighteen million, four hundred three thousand, eight hundred forty".