21443273808 has 40 divisors (see below), whose sum is σ = 60431045856. Its totient is φ = 6497961600.

The previous prime is 21443273807. The next prime is 21443273827. The reversal of 21443273808 is 80837234412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21443273808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443273807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20305603 + ... + 20306658.

Almost surely, 2^21443273808 is an apocalyptic number.

It is an amenable number.

21443273808 is an abundant number, since it is smaller than the sum of its proper divisors (38987772048).

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

21443273808 is a wasteful number, since it uses less digits than its factorization.

21443273808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40612283 (or 40612277 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 42.

The spelling of 21443273808 in words is "twenty-one billion, four hundred forty-three million, two hundred seventy-three thousand, eight hundred eight".