20404042 has 4 divisors (see below), whose sum is σ = 30606066. Its totient is φ = 10202020.

The previous prime is 20404039. The next prime is 20404049. The reversal of 20404042 is 24040402.

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., 11229201 + 9174841 = 3351^2 + 3029^2 .

It is not an unprimeable number, because it can be changed into a prime (20404049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5101009 + ... + 5101012.

Almost surely, 2^20404042 is an apocalyptic number.

20404042 is a deficient number, since it is larger than the sum of its proper divisors (10202024).

20404042 is a wasteful number, since it uses less digits than its factorization.

20404042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10202023.

The product of its (nonzero) digits is 256, while the sum is 16.

The square root of 20404042 is about 4517.0833510131. The cubic root of 20404042 is about 273.2574867220.

Adding to 20404042 its reverse (24040402), we get a palindrome (44444444).

The spelling of 20404042 in words is "twenty million, four hundred four thousand, forty-two".