20638538 has 12 divisors (see below), whose sum is σ = 31700178. Its totient is φ = 10077480.

The previous prime is 20638523. The next prime is 20638559. The reversal of 20638538 is 83583602.

It can be written as a sum of positive squares in only one way, i.e., 18861649 + 1776889 = 4343^2 + 1333^2 .

It is a Smith number, since the sum of its digits (35) 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 = 20638498 and 20638507.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 908 + ... + 6488.

Almost surely, 2^20638538 is an apocalyptic number.

20638538 is a deficient number, since it is larger than the sum of its proper divisors (11061640).

20638538 is an equidigital number, since it uses as much as digits as its factorization.

20638538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5669 (or 5626 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 20638538 is about 4542.9657713877. The cubic root of 20638538 is about 274.3003171737.

It can be divided in two parts, 2063 and 8538, that added together give a palindrome (10601).

The spelling of 20638538 in words is "twenty million, six hundred thirty-eight thousand, five hundred thirty-eight".