21043445025 has 12 divisors (see below), whose sum is σ = 34791829232. Its totient is φ = 11223170640.

The previous prime is 21043445021. The next prime is 21043445047. The reversal of 21043445025 is 52054434012.

It is not a de Polignac number, because 21043445025 - 2² = 21043445021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21043444983 and 21043445001.

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 in 11 ways as a sum of consecutive naturals, for example, 140289559 + ... + 140289708.

Almost surely, 2^21043445025 is an apocalyptic number.

21043445025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21043445025 is a deficient number, since it is larger than the sum of its proper divisors (13748384207).

21043445025 is a wasteful number, since it uses less digits than its factorization.

21043445025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280579280 (or 280579275 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 30.

Adding to 21043445025 its reverse (52054434012), we get a palindrome (73097879037).

The spelling of 21043445025 in words is "twenty-one billion, forty-three million, four hundred forty-five thousand, twenty-five".