21243033444 has 12 divisors (see below), whose sum is σ = 49567078064. Its totient is φ = 7081011144.

The previous prime is 21243033439. The next prime is 21243033463. The reversal of 21243033444 is 44433034212.

It is a happy number.

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

It is a super-2 number, since 2×21243033444² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885126382 + ... + 885126405.

Almost surely, 2^21243033444 is an apocalyptic number.

It is an amenable number.

21243033444 is an abundant number, since it is smaller than the sum of its proper divisors (28324044620).

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

21243033444 is a wasteful number, since it uses less digits than its factorization.

21243033444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770252794 (or 1770252792 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 30.

Adding to 21243033444 its reverse (44433034212), we get a palindrome (65676067656).

The spelling of 21243033444 in words is "twenty-one billion, two hundred forty-three million, thirty-three thousand, four hundred forty-four".