21404401423 has 4 divisors (see below), whose sum is σ = 21411536848. Its totient is φ = 21397266000.

The previous prime is 21404401363. The next prime is 21404401433. The reversal of 21404401423 is 32410440412.

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

It is a cyclic number.

It is not a de Polignac number, because 21404401423 - 2²⁹ = 20867530511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404401433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3563211 + ... + 3569212.

It is an arithmetic number, because the mean of its divisors is an integer number (5352884212).

Almost surely, 2^21404401423 is an apocalyptic number.

21404401423 is a deficient number, since it is larger than the sum of its proper divisors (7135425).

21404401423 is an equidigital number, since it uses as much as digits as its factorization.

21404401423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7135424.

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21404401423 its reverse (32410440412), we get a palindrome (53814841835).

The spelling of 21404401423 in words is "twenty-one billion, four hundred four million, four hundred one thousand, four hundred twenty-three".