21144400441 has 4 divisors (see below), whose sum is σ = 21146810112. Its totient is φ = 21141990772.

The previous prime is 21144400391. The next prime is 21144400451. The reversal of 21144400441 is 14400444112.

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 21144400441 - 2⁹ = 21144399929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144400451) 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, 1191625 + ... + 1209238.

It is an arithmetic number, because the mean of its divisors is an integer number (5286702528).

Almost surely, 2^21144400441 is an apocalyptic number.

It is an amenable number.

21144400441 is a deficient number, since it is larger than the sum of its proper divisors (2409671).

21144400441 is an equidigital number, since it uses as much as digits as its factorization.

21144400441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2409670.

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21144400441 its reverse (14400444112), we get a palindrome (35544844553).

The spelling of 21144400441 in words is "twenty-one billion, one hundred forty-four million, four hundred thousand, four hundred forty-one".