21143223444 has 72 divisors (see below), whose sum is σ = 57445032288. Its totient is φ = 6034996800.

The previous prime is 21143223407. The next prime is 21143223449. The reversal of 21143223444 is 44432234112.

It is a super-2 number, since 2×21143223444² (a number of 21 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143223449) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 600882 + ... + 635094.

Almost surely, 2^21143223444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21143223444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28722516144).

21143223444 is an abundant number, since it is smaller than the sum of its proper divisors (36301808844).

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

21143223444 is a wasteful number, since it uses less digits than its factorization.

21143223444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35285 (or 35276 counting only the distinct ones).

The product of its digits is 18432, while the sum is 30.

Adding to 21143223444 its reverse (44432234112), we get a palindrome (65575457556).

The spelling of 21143223444 in words is "twenty-one billion, one hundred forty-three million, two hundred twenty-three thousand, four hundred forty-four".