21221545224553 has 16 divisors (see below), whose sum is σ = 21495640420800. Its totient is φ = 20949220779840.

The previous prime is 21221545224497. The next prime is 21221545224557. The reversal of 21221545224553 is 35542254512212.

It is not a de Polignac number, because 21221545224553 - 2¹⁷ = 21221545093481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221545224557) 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, 171094683 + ... + 171218671.

It is an arithmetic number, because the mean of its divisors is an integer number (1343477526300).

Almost surely, 2^{21221545224553} is an apocalyptic number.

It is an amenable number.

21221545224553 is a deficient number, since it is larger than the sum of its proper divisors (274095196247).

21221545224553 is a wasteful number, since it uses less digits than its factorization.

21221545224553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131112.

The product of its digits is 960000, while the sum is 43.

Adding to 21221545224553 its reverse (35542254512212), we get a palindrome (56763799736765).

The spelling of 21221545224553 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred forty-five million, two hundred twenty-four thousand, five hundred fifty-three".