20908728 has 24 divisors (see below), whose sum is σ = 56628000. Its totient is φ = 6969552.

The previous prime is 20908711. The next prime is 20908747. The reversal of 20908728 is 82780902.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20908692 and 20908701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 145128 + ... + 145271.

It is an arithmetic number, because the mean of its divisors is an integer number (2359500).

Almost surely, 2^20908728 is an apocalyptic number.

It is an amenable number.

20908728 is an abundant number, since it is smaller than the sum of its proper divisors (35719272).

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

20908728 is a wasteful number, since it uses less digits than its factorization.

20908728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290411 (or 290404 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 20908728 is about 4572.6062590168. The cubic root of 20908728 is about 275.4921347377.

The spelling of 20908728 in words is "twenty million, nine hundred eight thousand, seven hundred twenty-eight".