20728040 has 64 divisors (see below), whose sum is σ = 48988800. Its totient is φ = 7883008.

The previous prime is 20728033. The next prime is 20728061. The reversal of 20728040 is 4082702.

It is a junction number, because it is equal to n+sod(n) for n = 20727997 and 20728015.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 124037 + ... + 124203.

It is an arithmetic number, because the mean of its divisors is an integer number (765450).

Almost surely, 2^20728040 is an apocalyptic number.

20728040 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 20728040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24494400).

20728040 is an abundant number, since it is smaller than the sum of its proper divisors (28260760).

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

20728040 is a wasteful number, since it uses less digits than its factorization.

20728040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 20728040 is about 4552.8057283394. The cubic root of 20728040 is about 274.6962596805.

The spelling of 20728040 in words is "twenty million, seven hundred twenty-eight thousand, forty".