20780928 has 128 divisors (see below), whose sum is σ = 70176000. Its totient is φ = 5930496.

The previous prime is 20780887. The next prime is 20780941. The reversal of 20780928 is 82908702.

It is a tau number, because it is divible by the number of its divisors (128).

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 = 20780892 and 20780901.

It is a congruent number.

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, 23763 + ... + 24621.

It is an arithmetic number, because the mean of its divisors is an integer number (548250).

Almost surely, 2^20780928 is an apocalyptic number.

20780928 is a gapful number since it is divisible by the number (28) 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 20780928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35088000).

20780928 is an abundant number, since it is smaller than the sum of its proper divisors (49395072).

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

20780928 is an equidigital number, since it uses as much as digits as its factorization.

20780928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 889 (or 871 counting only the distinct ones).

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

The square root of 20780928 is about 4558.6103145586. The cubic root of 20780928 is about 274.9296922192.

The spelling of 20780928 in words is "twenty million, seven hundred eighty thousand, nine hundred twenty-eight".