21440434404353 has 4 divisors (see below), whose sum is σ = 21444171630660. Its totient is φ = 21436697178048.

The previous prime is 21440434404341. The next prime is 21440434404421. The reversal of 21440434404353 is 35340443404412.

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 11161793219329 + 10278641185024 = 3340927^2 + 3206032^2 .

It is a cyclic number.

It is not a de Polignac number, because 21440434404353 - 2²⁴ = 21440417627137 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 21440434404353.

It is not an unprimeable number, because it can be changed into a prime (21440434404553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1868604548 + ... + 1868616021.

It is an arithmetic number, because the mean of its divisors is an integer number (5361042907665).

Almost surely, 2^{21440434404353} is an apocalyptic number.

It is an amenable number.

21440434404353 is a deficient number, since it is larger than the sum of its proper divisors (3737226307).

21440434404353 is an equidigital number, since it uses as much as digits as its factorization.

21440434404353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3737226306.

The product of its (nonzero) digits is 1105920, while the sum is 41.

Adding to 21440434404353 its reverse (35340443404412), we get a palindrome (56780877808765).

The spelling of 21440434404353 in words is "twenty-one trillion, four hundred forty billion, four hundred thirty-four million, four hundred four thousand, three hundred fifty-three".