21213444444553 has 16 divisors (see below), whose sum is σ = 22940123906304. Its totient is φ = 19540002735360.

The previous prime is 21213444444509. The next prime is 21213444444583. The reversal of 21213444444553 is 35544444431212.

It is a cyclic number.

It is not a de Polignac number, because 21213444444553 - 2¹³ = 21213444436361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21213444444583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19658026 + ... + 20709052.

It is an arithmetic number, because the mean of its divisors is an integer number (1433757744144).

Almost surely, 2^{21213444444553} is an apocalyptic number.

It is an amenable number.

21213444444553 is a deficient number, since it is larger than the sum of its proper divisors (1726679461751).

21213444444553 is a wasteful number, since it uses less digits than its factorization.

21213444444553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076352.

The product of its digits is 3686400, while the sum is 46.

Adding to 21213444444553 its reverse (35544444431212), we get a palindrome (56757888875765).

The spelling of 21213444444553 in words is "twenty-one trillion, two hundred thirteen billion, four hundred forty-four million, four hundred forty-four thousand, five hundred fifty-three".