20336640 has 104 divisors (see below), whose sum is σ = 65265888. Its totient is φ = 5406720.

The previous prime is 20336639. The next prime is 20336647. The reversal of 20336640 is 4663302.

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 20336640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20336647) by changing a digit.

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, 61275 + ... + 61605.

Almost surely, 2^20336640 is an apocalyptic number.

20336640 is a gapful number since it is divisible by the number (20) 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 20336640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32632944).

20336640 is an abundant number, since it is smaller than the sum of its proper divisors (44929248).

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

20336640 is an equidigital number, since it uses as much as digits as its factorization.

20336640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 24.

The square root of 20336640 is about 4509.6163916679. The cubic root of 20336640 is about 272.9562650492.

Adding to 20336640 its reverse (4663302), we get a palindrome (24999942).

The spelling of 20336640 in words is "twenty million, three hundred thirty-six thousand, six hundred forty".