21216211615543 has 8 divisors (see below), whose sum is σ = 24290166665088. Its totient is φ = 18153023484984.

The previous prime is 21216211615493. The next prime is 21216211615559. The reversal of 21216211615543 is 34551611261212.

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

It is a de Polignac number, because none of the positive numbers 2^k-21216211615543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21216211615496 and 21216211615505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216271615543) 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, 2691725521 + ... + 2691733402.

It is an arithmetic number, because the mean of its divisors is an integer number (3036270833136).

Almost surely, 2^{21216211615543} is an apocalyptic number.

21216211615543 is a deficient number, since it is larger than the sum of its proper divisors (3073955049545).

21216211615543 is an equidigital number, since it uses as much as digits as its factorization.

21216211615543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5383459493.

The product of its digits is 86400, while the sum is 40.

Adding to 21216211615543 its reverse (34551611261212), we get a palindrome (55767822876755).

The spelling of 21216211615543 in words is "twenty-one trillion, two hundred sixteen billion, two hundred eleven million, six hundred fifteen thousand, five hundred forty-three".