21251051441 has 4 divisors (see below), whose sum is σ = 21256738800. Its totient is φ = 21245364084.

The previous prime is 21251051431. The next prime is 21251051443. The reversal of 21251051441 is 14415015212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21251051441 - 2⁶ = 21251051377 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21251051441.

It is not an unprimeable number, because it can be changed into a prime (21251051443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2838071 + ... + 2845548.

It is an arithmetic number, because the mean of its divisors is an integer number (5314184700).

Almost surely, 2^21251051441 is an apocalyptic number.

It is an amenable number.

21251051441 is a deficient number, since it is larger than the sum of its proper divisors (5687359).

21251051441 is an equidigital number, since it uses as much as digits as its factorization.

21251051441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5687358.

The product of its (nonzero) digits is 1600, while the sum is 26.

Adding to 21251051441 its reverse (14415015212), we get a palindrome (35666066653).

The spelling of 21251051441 in words is "twenty-one billion, two hundred fifty-one million, fifty-one thousand, four hundred forty-one".