20728320 has 80 divisors (see below), whose sum is σ = 66290400. Its totient is φ = 5525504.

The previous prime is 20728291. The next prime is 20728339. The reversal of 20728320 is 2382702.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6331 + ... + 9029.

It is an arithmetic number, because the mean of its divisors is an integer number (828630).

Almost surely, 2^20728320 is an apocalyptic number.

20728320 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 20728320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33145200).

20728320 is an abundant number, since it is smaller than the sum of its proper divisors (45562080).

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

20728320 is an equidigital number, since it uses as much as digits as its factorization.

20728320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2725 (or 2709 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 20728320 is about 4552.8364785044. The cubic root of 20728320 is about 274.6974965656.

The spelling of 20728320 in words is "twenty million, seven hundred twenty-eight thousand, three hundred twenty".