20728280 has 16 divisors (see below), whose sum is σ = 46638720. Its totient is φ = 8291296.

The previous prime is 20728273. The next prime is 20728283. The reversal of 20728280 is 8282702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259064 + ... + 259143.

It is an arithmetic number, because the mean of its divisors is an integer number (2914920).

Almost surely, 2^20728280 is an apocalyptic number.

20728280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20728280 is an abundant number, since it is smaller than the sum of its proper divisors (25910440).

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

20728280 is a wasteful number, since it uses less digits than its factorization.

20728280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518218 (or 518214 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 20728280 is about 4552.8320856364. The cubic root of 20728280 is about 274.6973198684.

The spelling of 20728280 in words is "twenty million, seven hundred twenty-eight thousand, two hundred eighty".