18564640 has 48 divisors (see below), whose sum is σ = 45382680. Its totient is φ = 7168000.

The previous prime is 18564631. The next prime is 18564641. The reversal of 18564640 is 4646581.

It can be written as a sum of positive squares in 4 ways, for example, as 10061584 + 8503056 = 3172^2 + 2916^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18564596 and 18564605.

It is not an unprimeable number, because it can be changed into a prime (18564641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2640 + ... + 6640.

Almost surely, 2^18564640 is an apocalyptic number.

18564640 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 18564640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22691340).

18564640 is an abundant number, since it is smaller than the sum of its proper divisors (26818040).

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

18564640 is a wasteful number, since it uses less digits than its factorization.

18564640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4045 (or 4037 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 18564640 is about 4308.6703285352. The cubic root of 18564640 is about 264.7862997692.

The spelling of 18564640 in words is "eighteen million, five hundred sixty-four thousand, six hundred forty".