18940640 has 48 divisors (see below), whose sum is σ = 45804528. Its totient is φ = 7397376.

The previous prime is 18940627. The next prime is 18940651. The reversal of 18940640 is 4604981.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 18940597 and 18940606.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5504 + ... + 8256.

It is an arithmetic number, because the mean of its divisors is an integer number (954261).

Almost surely, 2^18940640 is an apocalyptic number.

18940640 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 18940640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22902264).

18940640 is an abundant number, since it is smaller than the sum of its proper divisors (26863888).

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

18940640 is a wasteful number, since it uses less digits than its factorization.

18940640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2811 (or 2803 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 18940640 is about 4352.0845580021. The cubic root of 18940640 is about 266.5619866910.

The spelling of 18940640 in words is "eighteen million, nine hundred forty thousand, six hundred forty".