21043445026 has 4 divisors (see below), whose sum is σ = 31565167542. Its totient is φ = 10521722512.

The previous prime is 21043445021. The next prime is 21043445047. The reversal of 21043445026 is 62054434012.

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., 14725579801 + 6317865225 = 121349^2 + 79485^2 .

It is a Smith number, since the sum of its digits (31) 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 (21043445021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5260861255 + ... + 5260861258.

Almost surely, 2^21043445026 is an apocalyptic number.

21043445026 is a deficient number, since it is larger than the sum of its proper divisors (10521722516).

21043445026 is a wasteful number, since it uses less digits than its factorization.

21043445026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10521722515.

The product of its (nonzero) digits is 23040, while the sum is 31.

Adding to 21043445026 its reverse (62054434012), we get a palindrome (83097879038).

The spelling of 21043445026 in words is "twenty-one billion, forty-three million, four hundred forty-five thousand, twenty-six".