21404123305 has 8 divisors (see below), whose sum is σ = 25949741832. Its totient is φ = 16946769408.

The previous prime is 21404123281. The next prime is 21404123317. The reversal of 21404123305 is 50332140412.

It can be written as a sum of positive squares in 4 ways, for example, as 7825348521 + 13578774784 = 88461^2 + 116528^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21404123305 - 2⁹ = 21404122793 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 21404123305.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22065622 + ... + 22066591.

It is an arithmetic number, because the mean of its divisors is an integer number (3243717729).

Almost surely, 2^21404123305 is an apocalyptic number.

It is an amenable number.

21404123305 is a deficient number, since it is larger than the sum of its proper divisors (4545618527).

21404123305 is an equidigital number, since it uses as much as digits as its factorization.

21404123305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44132315.

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21404123305 its reverse (50332140412), we get a palindrome (71736263717).

The spelling of 21404123305 in words is "twenty-one billion, four hundred four million, one hundred twenty-three thousand, three hundred five".