21144203423 has 16 divisors (see below), whose sum is σ = 24915576576. Its totient is φ = 17566960320.

The previous prime is 21144203389. The next prime is 21144203453. The reversal of 21144203423 is 32430244112.

It is not a de Polignac number, because 21144203423 - 2⁶ = 21144203359 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21144203392 and 21144203401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144203453) 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 15 ways as a sum of consecutive naturals, for example, 228686 + ... + 307547.

It is an arithmetic number, because the mean of its divisors is an integer number (1557223536).

Almost surely, 2^21144203423 is an apocalyptic number.

21144203423 is a deficient number, since it is larger than the sum of its proper divisors (3771373153).

21144203423 is a wasteful number, since it uses less digits than its factorization.

21144203423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536414.

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21144203423 its reverse (32430244112), we get a palindrome (53574447535).

The spelling of 21144203423 in words is "twenty-one billion, one hundred forty-four million, two hundred three thousand, four hundred twenty-three".