21515445221153 has 8 divisors (see below), whose sum is σ = 23208277975848. Its totient is φ = 19828012253184.

The previous prime is 21515445221129. The next prime is 21515445221161. The reversal of 21515445221153 is 35112254451512.

It can be written as a sum of positive squares in 4 ways, for example, as 174851931409 + 21340593289744 = 418153^2 + 4619588^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21515445221153 - 2¹⁴ = 21515445204769 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21515445221153.

It is not an unprimeable number, because it can be changed into a prime (21515445221653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1349938400 + ... + 1349954337.

It is an arithmetic number, because the mean of its divisors is an integer number (2901034746981).

Almost surely, 2^{21515445221153} is an apocalyptic number.

It is an amenable number.

21515445221153 is a deficient number, since it is larger than the sum of its proper divisors (1692832754695).

21515445221153 is a wasteful number, since it uses less digits than its factorization.

21515445221153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2699893363.

The product of its digits is 240000, while the sum is 41.

Adding to 21515445221153 its reverse (35112254451512), we get a palindrome (56627699672665).

The spelling of 21515445221153 in words is "twenty-one trillion, five hundred fifteen billion, four hundred forty-five million, two hundred twenty-one thousand, one hundred fifty-three".