21216361515503 has 16 divisors (see below), whose sum is σ = 26659847675904. Its totient is φ = 16402054707360.

The previous prime is 21216361515451. The next prime is 21216361515529. The reversal of 21216361515503 is 30551516361212.

It is not a de Polignac number, because 21216361515503 - 2¹⁸ = 21216361253359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216361515563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1084782200 + ... + 1084801757.

It is an arithmetic number, because the mean of its divisors is an integer number (1666240479744).

Almost surely, 2^{21216361515503} is an apocalyptic number.

21216361515503 is a deficient number, since it is larger than the sum of its proper divisors (5443486160401).

21216361515503 is a wasteful number, since it uses less digits than its factorization.

21216361515503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2169584102.

The product of its (nonzero) digits is 162000, while the sum is 41.

Adding to 21216361515503 its reverse (30551516361212), we get a palindrome (51767877876715).

The spelling of 21216361515503 in words is "twenty-one trillion, two hundred sixteen billion, three hundred sixty-one million, five hundred fifteen thousand, five hundred three".