20421442 has 4 divisors (see below), whose sum is σ = 30632166. Its totient is φ = 10210720.

The previous prime is 20421433. The next prime is 20421449. The reversal of 20421442 is 24412402.

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., 20421361 + 81 = 4519^2 + 9^2 .

It is not an unprimeable number, because it can be changed into a prime (20421449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5105359 + ... + 5105362.

Almost surely, 2^20421442 is an apocalyptic number.

20421442 is a deficient number, since it is larger than the sum of its proper divisors (10210724).

20421442 is a wasteful number, since it uses less digits than its factorization.

20421442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10210723.

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 20421442 is about 4519.0089621509. The cubic root of 20421442 is about 273.3351401163.

Adding to 20421442 its reverse (24412402), we get a palindrome (44833844).

The spelling of 20421442 in words is "twenty million, four hundred twenty-one thousand, four hundred forty-two".