18443640 has 64 divisors (see below), whose sum is σ = 58592160. Its totient is φ = 4628480.

The previous prime is 18443617. The next prime is 18443653. The reversal of 18443640 is 4634481.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 18443598 and 18443607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2481 + ... + 6560.

Almost surely, 2^18443640 is an apocalyptic number.

18443640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18443640 is an abundant number, since it is smaller than the sum of its proper divisors (40148520).

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

18443640 is a wasteful number, since it uses less digits than its factorization.

18443640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9072 (or 9068 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 18443640 is about 4294.6059190571. The cubic root of 18443640 is about 264.2097735826.

The spelling of 18443640 in words is "eighteen million, four hundred forty-three thousand, six hundred forty".