18821040 has 160 divisors (see below), whose sum is σ = 70709760. Its totient is φ = 4042752.

The previous prime is 18821027. The next prime is 18821051. The reversal of 18821040 is 4012881.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 18821040.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28231 + ... + 28889.

It is an arithmetic number, because the mean of its divisors is an integer number (441936).

Almost surely, 2^18821040 is an apocalyptic number.

18821040 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 18821040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35354880).

18821040 is an abundant number, since it is smaller than the sum of its proper divisors (51888720).

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

18821040 is a wasteful number, since it uses less digits than its factorization.

18821040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699 (or 693 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 18821040 is about 4338.3222563567. The cubic root of 18821040 is about 265.9997361823. Note that the first 3 decimals are identical.

The spelling of 18821040 in words is "eighteen million, eight hundred twenty-one thousand, forty".