21312043415543 has 8 divisors (see below), whose sum is σ = 22573531111680. Its totient is φ = 20051426617600.

The previous prime is 21312043415521. The next prime is 21312043415581. The reversal of 21312043415543 is 34551434021312.

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 21312043415543 - 2¹⁸ = 21312043153399 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21312043415497 and 21312043415506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312043415743) 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, 217674158 + ... + 217772043.

It is an arithmetic number, because the mean of its divisors is an integer number (2821691388960).

Almost surely, 2^{21312043415543} is an apocalyptic number.

21312043415543 is a deficient number, since it is larger than the sum of its proper divisors (1261487696137).

21312043415543 is a wasteful number, since it uses less digits than its factorization.

21312043415543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435449097.

The product of its (nonzero) digits is 172800, while the sum is 38.

Adding to 21312043415543 its reverse (34551434021312), we get a palindrome (55863477436855).

The spelling of 21312043415543 in words is "twenty-one trillion, three hundred twelve billion, forty-three million, four hundred fifteen thousand, five hundred forty-three".