20517128 has 16 divisors (see below), whose sum is σ = 38539260. Its totient is φ = 10240000.

The previous prime is 20517121. The next prime is 20517157. The reversal of 20517128 is 82171502.

It can be written as a sum of positive squares in 2 ways, for example, as 20448484 + 68644 = 4522^2 + 262^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20517097 and 20517106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20517121) 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, 3128 + ... + 7128.

Almost surely, 2^20517128 is an apocalyptic number.

It is an amenable number.

20517128 is a deficient number, since it is larger than the sum of its proper divisors (18022132).

20517128 is a wasteful number, since it uses less digits than its factorization.

20517128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4648 (or 4644 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 20517128 is about 4529.5836453255. The cubic root of 20517128 is about 273.7613849577.

The spelling of 20517128 in words is "twenty million, five hundred seventeen thousand, one hundred twenty-eight".