18038640 has 40 divisors (see below), whose sum is σ = 55920528. Its totient is φ = 4810240.

The previous prime is 18038597. The next prime is 18038651. The reversal of 18038640 is 4683081.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

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 = 18038598 and 18038607.

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 7 ways as a sum of consecutive naturals, for example, 37341 + ... + 37820.

Almost surely, 2^18038640 is an apocalyptic number.

18038640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18038640 is an abundant number, since it is smaller than the sum of its proper divisors (37881888).

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

18038640 is a wasteful number, since it uses less digits than its factorization.

18038640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75177 (or 75171 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 18038640 is about 4247.1920135544. The cubic root of 18038640 is about 262.2615340000.

The spelling of 18038640 in words is "eighteen million, thirty-eight thousand, six hundred forty".