18543640 has 32 divisors (see below), whose sum is σ = 42515280. Its totient is φ = 7276672.

The previous prime is 18543619. The next prime is 18543643. The reversal of 18543640 is 4634581.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18543643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2254 + ... + 6493.

Almost surely, 2^18543640 is an apocalyptic number.

18543640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18543640 is an abundant number, since it is smaller than the sum of its proper divisors (23971640).

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

18543640 is a wasteful number, since it uses less digits than its factorization.

18543640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8811 (or 8807 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 18543640 is about 4306.2326922729. The cubic root of 18543640 is about 264.6864215371.

The spelling of 18543640 in words is "eighteen million, five hundred forty-three thousand, six hundred forty".