21513443443 has 8 divisors (see below), whose sum is σ = 22647107520. Its totient is φ = 20379917160.

The previous prime is 21513443423. The next prime is 21513443489. The reversal of 21513443443 is 34434431512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21513443443 - 2⁵ = 21513443411 is a prime.

It is a super-4 number, since 4×21513443443⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21513443399 and 21513443408.

It is not an unprimeable number, because it can be changed into a prime (21513443423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 494148 + ... + 535918.

It is an arithmetic number, because the mean of its divisors is an integer number (2830888440).

Almost surely, 2^21513443443 is an apocalyptic number.

21513443443 is a deficient number, since it is larger than the sum of its proper divisors (1133664077).

21513443443 is a wasteful number, since it uses less digits than its factorization.

21513443443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68897.

The product of its digits is 69120, while the sum is 34.

Adding to 21513443443 its reverse (34434431512), we get a palindrome (55947874955).

The spelling of 21513443443 in words is "twenty-one billion, five hundred thirteen million, four hundred forty-three thousand, four hundred forty-three".