21216210516347 has 64 divisors (see below), whose sum is σ = 27113693967360. Its totient is φ = 16122039897600.

The previous prime is 21216210516341. The next prime is 21216210516373. The reversal of 21216210516347 is 74361501261212.

It is not a de Polignac number, because 21216210516347 - 2²⁰ = 21216209467771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21216210516341) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1634650304 + ... + 1634663282.

It is an arithmetic number, because the mean of its divisors is an integer number (423651468240).

Almost surely, 2^{21216210516347} is an apocalyptic number.

21216210516347 is a deficient number, since it is larger than the sum of its proper divisors (5897483451013).

21216210516347 is a wasteful number, since it uses less digits than its factorization.

21216210516347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15444.

The product of its (nonzero) digits is 120960, while the sum is 41.

Adding to 21216210516347 its reverse (74361501261212), we get a palindrome (95577711777559).

The spelling of 21216210516347 in words is "twenty-one trillion, two hundred sixteen billion, two hundred ten million, five hundred sixteen thousand, three hundred forty-seven".