20138242 has 4 divisors (see below), whose sum is σ = 30207366. Its totient is φ = 10069120.

The previous prime is 20138221. The next prime is 20138243. The reversal of 20138242 is 24283102.

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., 11895601 + 8242641 = 3449^2 + 2871^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20138243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5034559 + ... + 5034562.

Almost surely, 2^20138242 is an apocalyptic number.

20138242 is a deficient number, since it is larger than the sum of its proper divisors (10069124).

20138242 is a wasteful number, since it uses less digits than its factorization.

20138242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10069123.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 20138242 is about 4487.5652641494. The cubic root of 20138242 is about 272.0657370670.

The spelling of 20138242 in words is "twenty million, one hundred thirty-eight thousand, two hundred forty-two".