20638738 has 4 divisors (see below), whose sum is σ = 30958110. Its totient is φ = 10319368.

The previous prime is 20638733. The next prime is 20638741. The reversal of 20638738 is 83783602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12837889 + 7800849 = 3583^2 + 2793^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20638697 and 20638706.

It is not an unprimeable number, because it can be changed into a prime (20638733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5159683 + ... + 5159686.

Almost surely, 2^20638738 is an apocalyptic number.

20638738 is a deficient number, since it is larger than the sum of its proper divisors (10319372).

20638738 is a wasteful number, since it uses less digits than its factorization.

20638738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10319371.

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 20638738 is about 4542.9877833866. The cubic root of 20638738 is about 274.3012032166.

It can be divided in two parts, 2063 and 8738, that added together give a palindrome (10801).

The spelling of 20638738 in words is "twenty million, six hundred thirty-eight thousand, seven hundred thirty-eight".