20704728 has 32 divisors (see below), whose sum is σ = 56468160. Its totient is φ = 6274080.

The previous prime is 20704727. The next prime is 20704729. The reversal of 20704728 is 82740702.

It is an interprime number because it is at equal distance from previous prime (20704727) and next prime (20704729).

It is a junction number, because it is equal to n+sod(n) for n = 20704695 and 20704704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20704721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38950 + ... + 39477.

It is an arithmetic number, because the mean of its divisors is an integer number (1764630).

Almost surely, 2^20704728 is an apocalyptic number.

It is an amenable number.

20704728 is an abundant number, since it is smaller than the sum of its proper divisors (35763432).

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

20704728 is a wasteful number, since it uses less digits than its factorization.

20704728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78447 (or 78443 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 20704728 is about 4550.2448285779. The cubic root of 20704728 is about 274.5932410742.

The spelling of 20704728 in words is "twenty million, seven hundred four thousand, seven hundred twenty-eight".