20447728 has 40 divisors (see below), whose sum is σ = 45870080. Its totient is φ = 8648640.

The previous prime is 20447723. The next prime is 20447729. The reversal of 20447728 is 82774402.

It is a junction number, because it is equal to n+sod(n) for n = 20447693 and 20447702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20447723) 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, 7693 + ... + 10003.

It is an arithmetic number, because the mean of its divisors is an integer number (1146752).

Almost surely, 2^20447728 is an apocalyptic number.

20447728 is a gapful number since it is divisible by the number (28) 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 20447728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22935040).

20447728 is an abundant number, since it is smaller than the sum of its proper divisors (25422352).

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

20447728 is a wasteful number, since it uses less digits than its factorization.

20447728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2405 (or 2399 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 34.

The square root of 20447728 is about 4521.9164078961. The cubic root of 20447728 is about 273.4523666888.

The spelling of 20447728 in words is "twenty million, four hundred forty-seven thousand, seven hundred twenty-eight".