21615543340253 has 16 divisors (see below), whose sum is σ = 22495977504000. Its totient is φ = 20744126925312.

The previous prime is 21615543340241. The next prime is 21615543340283. The reversal of 21615543340253 is 35204334551612.

It is a cyclic number.

It is not a de Polignac number, because 21615543340253 - 2¹⁸ = 21615543078109 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 (21615543340213) 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, 102028208 + ... + 102239846.

It is an arithmetic number, because the mean of its divisors is an integer number (1405998594000).

Almost surely, 2^{21615543340253} is an apocalyptic number.

It is an amenable number.

21615543340253 is a deficient number, since it is larger than the sum of its proper divisors (880434163747).

21615543340253 is a wasteful number, since it uses less digits than its factorization.

21615543340253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232924.

The product of its (nonzero) digits is 1296000, while the sum is 44.

Adding to 21615543340253 its reverse (35204334551612), we get a palindrome (56819877891865).

The spelling of 21615543340253 in words is "twenty-one trillion, six hundred fifteen billion, five hundred forty-three million, three hundred forty thousand, two hundred fifty-three".