21216201015523 has 16 divisors (see below), whose sum is σ = 21618509230080. Its totient is φ = 20816904640000.

The previous prime is 21216201015521. The next prime is 21216201015551. The reversal of 21216201015523 is 32551010261212.

It is not a de Polignac number, because 21216201015523 - 2¹ = 21216201015521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216201015521) 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, 21199038 + ... + 22177276.

It is an arithmetic number, because the mean of its divisors is an integer number (1351156826880).

Almost surely, 2^{21216201015523} is an apocalyptic number.

21216201015523 is a deficient number, since it is larger than the sum of its proper divisors (402308214557).

21216201015523 is a wasteful number, since it uses less digits than its factorization.

21216201015523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 979778.

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 21216201015523 its reverse (32551010261212), we get a palindrome (53767211276735).

The spelling of 21216201015523 in words is "twenty-one trillion, two hundred sixteen billion, two hundred one million, fifteen thousand, five hundred twenty-three".