21643155024 has 80 divisors (see below), whose sum is σ = 57063579840. Its totient is φ = 7066608640.

The previous prime is 21643154987. The next prime is 21643155059. The reversal of 21643155024 is 42055134612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 782194 + ... + 809390.

It is an arithmetic number, because the mean of its divisors is an integer number (713294748).

Almost surely, 2^21643155024 is an apocalyptic number.

21643155024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21643155024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28531789920).

21643155024 is an abundant number, since it is smaller than the sum of its proper divisors (35420424816).

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

21643155024 is a wasteful number, since it uses less digits than its factorization.

21643155024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27548 (or 27542 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 21643155024 its reverse (42055134612), we get a palindrome (63698289636).

The spelling of 21643155024 in words is "twenty-one billion, six hundred forty-three million, one hundred fifty-five thousand, twenty-four".