20728736 has 48 divisors (see below), whose sum is σ = 48263040. Its totient is φ = 8574720.

The previous prime is 20728733. The next prime is 20728759. The reversal of 20728736 is 63782702.

It is a junction number, because it is equal to n+sod(n) for n = 20728696 and 20728705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4901 + ... + 8091.

It is an arithmetic number, because the mean of its divisors is an integer number (1005480).

Almost surely, 2^20728736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20728736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24131520).

20728736 is an abundant number, since it is smaller than the sum of its proper divisors (27534304).

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

20728736 is a wasteful number, since it uses less digits than its factorization.

20728736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3237 (or 3229 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 35.

The square root of 20728736 is about 4552.8821640802. The cubic root of 20728736 is about 274.6993342027.

The spelling of 20728736 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred thirty-six".