21523104455423 has 4 divisors (see below), whose sum is σ = 21523631338968. Its totient is φ = 21522577571880.

The previous prime is 21523104455417. The next prime is 21523104455467. The reversal of 21523104455423 is 32455440132512.

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 21523104455423 - 2⁴ = 21523104455407 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 (21523104455623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263380493 + ... + 263462198.

It is an arithmetic number, because the mean of its divisors is an integer number (5380907834742).

Almost surely, 2^{21523104455423} is an apocalyptic number.

21523104455423 is a deficient number, since it is larger than the sum of its proper divisors (526883545).

21523104455423 is an equidigital number, since it uses as much as digits as its factorization.

21523104455423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526883544.

The product of its (nonzero) digits is 576000, while the sum is 41.

Adding to 21523104455423 its reverse (32455440132512), we get a palindrome (53978544587935).

The spelling of 21523104455423 in words is "twenty-one trillion, five hundred twenty-three billion, one hundred four million, four hundred fifty-five thousand, four hundred twenty-three".