21216361515331 has 4 divisors (see below), whose sum is σ = 21295232748000. Its totient is φ = 21137490282664.

The previous prime is 21216361515257. The next prime is 21216361515389. The reversal of 21216361515331 is 13351516361212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21216361515331 - 2⁹ = 21216361514819 is a prime.

It is a super-2 number, since 2×21216361515331² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216361515631) 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, 39435615931 + ... + 39435616468.

It is an arithmetic number, because the mean of its divisors is an integer number (5323808187000).

Almost surely, 2^{21216361515331} is an apocalyptic number.

21216361515331 is a deficient number, since it is larger than the sum of its proper divisors (78871232669).

21216361515331 is an equidigital number, since it uses as much as digits as its factorization.

21216361515331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78871232668.

The product of its digits is 97200, while the sum is 40.

Adding to 21216361515331 its reverse (13351516361212), we get a palindrome (34567877876543).

The spelling of 21216361515331 in words is "twenty-one trillion, two hundred sixteen billion, three hundred sixty-one million, five hundred fifteen thousand, three hundred thirty-one".