21530246144 has 88 divisors (see below), whose sum is σ = 47313801216. Its totient is φ = 9711104000.

The previous prime is 21530246117. The next prime is 21530246219. The reversal of 21530246144 is 44164203512.

It is a tau number, because it is divible by the number of its divisors (88).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 21530246144.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1468289 + ... + 1482879.

It is an arithmetic number, because the mean of its divisors is an integer number (537656832).

Almost surely, 2^21530246144 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 21530246144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23656900608).

21530246144 is an abundant number, since it is smaller than the sum of its proper divisors (25783555072).

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

21530246144 is a wasteful number, since it uses less digits than its factorization.

21530246144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14753 (or 14735 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

Adding to 21530246144 its reverse (44164203512), we get a palindrome (65694449656).

The spelling of 21530246144 in words is "twenty-one billion, five hundred thirty million, two hundred forty-six thousand, one hundred forty-four".