20648440 has 64 divisors (see below), whose sum is σ = 49572000. Its totient is φ = 7718400.

The previous prime is 20648417. The next prime is 20648443. The reversal of 20648440 is 4484602.

It is a junction number, because it is equal to n+sod(n) for n = 20648399 and 20648408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20648443) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 76626 + ... + 76894.

Almost surely, 2^20648440 is an apocalyptic number.

20648440 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 20648440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24786000).

20648440 is an abundant number, since it is smaller than the sum of its proper divisors (28923560).

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

20648440 is a wasteful number, since it uses less digits than its factorization.

20648440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 28.

The square root of 20648440 is about 4544.0554574081. The cubic root of 20648440 is about 274.3441782824.

The spelling of 20648440 in words is "twenty million, six hundred forty-eight thousand, four hundred forty".