21213543315256 has 16 divisors (see below), whose sum is σ = 39775680861840. Its totient is φ = 10606695085440.

The previous prime is 21213543315247. The next prime is 21213543315259. The reversal of 21213543315256 is 65251334531212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213543315259) 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, 8385460 + ... + 10618051.

It is an arithmetic number, because the mean of its divisors is an integer number (2485980053865).

Almost surely, 2^{21213543315256} is an apocalyptic number.

It is an amenable number.

21213543315256 is a deficient number, since it is larger than the sum of its proper divisors (18562137546584).

21213543315256 is a wasteful number, since it uses less digits than its factorization.

21213543315256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19143054 (or 19143050 counting only the distinct ones).

The product of its digits is 648000, while the sum is 43.

Adding to 21213543315256 its reverse (65251334531212), we get a palindrome (86464877846468).

The spelling of 21213543315256 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred fifteen thousand, two hundred fifty-six".