20317728 has 24 divisors (see below), whose sum is σ = 53334288. Its totient is φ = 6772544.

The previous prime is 20317727. The next prime is 20317751. The reversal of 20317728 is 82771302.

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

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20317695 and 20317704.

It is not an unprimeable number, because it can be changed into a prime (20317723) 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, 105726 + ... + 105917.

It is an arithmetic number, because the mean of its divisors is an integer number (2222262).

Almost surely, 2^20317728 is an apocalyptic number.

It is an amenable number.

20317728 is an abundant number, since it is smaller than the sum of its proper divisors (33016560).

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

20317728 is a wasteful number, since it uses less digits than its factorization.

20317728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211656 (or 211648 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 20317728 is about 4507.5190515404. The cubic root of 20317728 is about 272.8716271757.

The spelling of 20317728 in words is "twenty million, three hundred seventeen thousand, seven hundred twenty-eight".