21443421133 has 4 divisors (see below), whose sum is σ = 21446627868. Its totient is φ = 21440214400.

The previous prime is 21443421127. The next prime is 21443421143. The reversal of 21443421133 is 33112434412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2793968164 + 18649452969 = 52858^2 + 136563^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443421133 - 2⁵ = 21443421101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443421113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1593316 + ... + 1606717.

It is an arithmetic number, because the mean of its divisors is an integer number (5361656967).

Almost surely, 2^21443421133 is an apocalyptic number.

It is an amenable number.

21443421133 is a deficient number, since it is larger than the sum of its proper divisors (3206735).

21443421133 is an equidigital number, since it uses as much as digits as its factorization.

21443421133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3206734.

The product of its digits is 6912, while the sum is 28.

Adding to 21443421133 its reverse (33112434412), we get a palindrome (54555855545).

The spelling of 21443421133 in words is "twenty-one billion, four hundred forty-three million, four hundred twenty-one thousand, one hundred thirty-three".