21113404441 has 4 divisors (see below), whose sum is σ = 21841452900. Its totient is φ = 20385355984.

The previous prime is 21113404397. The next prime is 21113404451. The reversal of 21113404441 is 14440431112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6289124416 + 14824280025 = 79304^2 + 121755^2 .

It is a cyclic number.

It is not a de Polignac number, because 21113404441 - 2²¹ = 21111307289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21113404451) 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, 364024186 + ... + 364024243.

It is an arithmetic number, because the mean of its divisors is an integer number (5460363225).

Almost surely, 2^21113404441 is an apocalyptic number.

It is an amenable number.

21113404441 is a deficient number, since it is larger than the sum of its proper divisors (728048459).

21113404441 is an equidigital number, since it uses as much as digits as its factorization.

21113404441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728048458.

The product of its (nonzero) digits is 1536, while the sum is 25.

Adding to 21113404441 its reverse (14440431112), we get a palindrome (35553835553).

The spelling of 21113404441 in words is "twenty-one billion, one hundred thirteen million, four hundred four thousand, four hundred forty-one".