21513425444320 has 192 divisors, whose sum is σ = 51726300240384. Its totient is φ = 8454419251200.

The previous prime is 21513425444309. The next prime is 21513425444321. The reversal of 21513425444320 is 2344452431512.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513425444321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1127942304 + ... + 1127961376.

It is an arithmetic number, because the mean of its divisors is an integer number (269407813752).

Almost surely, 2^{21513425444320} is an apocalyptic number.

21513425444320 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 21513425444320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25863150120192).

21513425444320 is an abundant number, since it is smaller than the sum of its proper divisors (30212874796064).

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

21513425444320 is a wasteful number, since it uses less digits than its factorization.

21513425444320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19725 (or 19717 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 40.

Adding to 21513425444320 its reverse (2344452431512), we get a palindrome (23857877875832).

The spelling of 21513425444320 in words is "twenty-one trillion, five hundred thirteen billion, four hundred twenty-five million, four hundred forty-four thousand, three hundred twenty".