21423540444 has 12 divisors (see below), whose sum is σ = 49988261064. Its totient is φ = 7141180144.

The previous prime is 21423540443. The next prime is 21423540493. The reversal of 21423540444 is 44404532412.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423540443) 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 3 ways as a sum of consecutive naturals, for example, 892647507 + ... + 892647530.

It is an arithmetic number, because the mean of its divisors is an integer number (4165688422).

Almost surely, 2^21423540444 is an apocalyptic number.

It is an amenable number.

21423540444 is an abundant number, since it is smaller than the sum of its proper divisors (28564720620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21423540444 is a wasteful number, since it uses less digits than its factorization.

21423540444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1785295044 (or 1785295042 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 33.

The spelling of 21423540444 in words is "twenty-one billion, four hundred twenty-three million, five hundred forty thousand, four hundred forty-four".