21243035425 has 6 divisors (see below), whose sum is σ = 26341363958. Its totient is φ = 16994428320.

The previous prime is 21243035353. The next prime is 21243035431. The reversal of 21243035425 is 52453034212.

It can be written as a sum of positive squares in 3 ways, for example, as 254849296 + 20988186129 = 15964^2 + 144873^2 .

It is not a de Polignac number, because 21243035425 - 2²⁹ = 20706164513 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 424860684 + ... + 424860733.

Almost surely, 2^21243035425 is an apocalyptic number.

21243035425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21243035425 is a deficient number, since it is larger than the sum of its proper divisors (5098328533).

21243035425 is an equidigital number, since it uses as much as digits as its factorization.

21243035425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849721427 (or 849721422 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 31.

Adding to 21243035425 its reverse (52453034212), we get a palindrome (73696069637).

The spelling of 21243035425 in words is "twenty-one billion, two hundred forty-three million, thirty-five thousand, four hundred twenty-five".