21113251543 has 8 divisors (see below), whose sum is σ = 21160297440. Its totient is φ = 21066239520.

The previous prime is 21113251517. The next prime is 21113251559. The reversal of 21113251543 is 34515231112.

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 21113251543 - 2¹³ = 21113243351 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 (21113254543) 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, 1546678 + ... + 1560268.

It is an arithmetic number, because the mean of its divisors is an integer number (2645037180).

Almost surely, 2^21113251543 is an apocalyptic number.

21113251543 is a deficient number, since it is larger than the sum of its proper divisors (47045897).

21113251543 is a wasteful number, since it uses less digits than its factorization.

21113251543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16937.

The product of its digits is 3600, while the sum is 28.

Adding to 21113251543 its reverse (34515231112), we get a palindrome (55628482655).

The spelling of 21113251543 in words is "twenty-one billion, one hundred thirteen million, two hundred fifty-one thousand, five hundred forty-three".