21153144544 has 96 divisors (see below), whose sum is σ = 48152966400. Its totient is φ = 8959887360.

The previous prime is 21153144541. The next prime is 21153144547. The reversal of 21153144544 is 44544135112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21153144541) and next prime (21153144547).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153144541) 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, 7502367 + ... + 7505185.

It is an arithmetic number, because the mean of its divisors is an integer number (501593400).

Almost surely, 2^21153144544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21153144544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24076483200).

21153144544 is an abundant number, since it is smaller than the sum of its proper divisors (26999821856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21153144544 is a wasteful number, since it uses less digits than its factorization.

21153144544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3216 (or 3208 counting only the distinct ones).

The product of its digits is 38400, while the sum is 34.

Adding to 21153144544 its reverse (44544135112), we get a palindrome (65697279656).

The spelling of 21153144544 in words is "twenty-one billion, one hundred fifty-three million, one hundred forty-four thousand, five hundred forty-four".