21144411500520 has 256 divisors, whose sum is σ = 79093333094400. Its totient is φ = 4393213839360.

The previous prime is 21144411500503. The next prime is 21144411500543. The reversal of 21144411500520 is 2500511444112.

It is a super-2 number, since 2×21144411500520² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 99029317 + ... + 99242603.

It is an arithmetic number, because the mean of its divisors is an integer number (308958332400).

Almost surely, 2^{21144411500520} is an apocalyptic number.

21144411500520 is a gapful number since it is divisible by the number (20) 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 21144411500520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39546666547200).

21144411500520 is an abundant number, since it is smaller than the sum of its proper divisors (57948921593880).

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

21144411500520 is a wasteful number, since it uses less digits than its factorization.

21144411500520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224048 (or 224044 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 30.

Adding to 21144411500520 its reverse (2500511444112), we get a palindrome (23644922944632).

The spelling of 21144411500520 in words is "twenty-one trillion, one hundred forty-four billion, four hundred eleven million, five hundred thousand, five hundred twenty".