21573735943 has 4 divisors (see below), whose sum is σ = 21591010000. Its totient is φ = 21556461888.

The previous prime is 21573735923. The next prime is 21573735949. The reversal of 21573735943 is 34953737512.

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

It is a cyclic number.

It is not a de Polignac number, because 21573735943 - 2²⁵ = 21540181511 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 (21573735949) 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, 8635155 + ... + 8637652.

It is an arithmetic number, because the mean of its divisors is an integer number (5397752500).

Almost surely, 2^21573735943 is an apocalyptic number.

21573735943 is a deficient number, since it is larger than the sum of its proper divisors (17274057).

21573735943 is a wasteful number, since it uses less digits than its factorization.

21573735943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17274056.

The product of its digits is 2381400, while the sum is 49.

The spelling of 21573735943 in words is "twenty-one billion, five hundred seventy-three million, seven hundred thirty-five thousand, nine hundred forty-three".