21113354364520 has 512 divisors, whose sum is σ = 55776986726400. Its totient is φ = 7112448000000.

The previous prime is 21113354364499. The next prime is 21113354364523. The reversal of 21113354364520 is 2546345331112.

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

It is not an unprimeable number, because it can be changed into a prime (21113354364523) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 43000721475 + ... + 43000721965.

It is an arithmetic number, because the mean of its divisors is an integer number (108939427200).

Almost surely, 2^{21113354364520} is an apocalyptic number.

21113354364520 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 21113354364520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27888493363200).

21113354364520 is an abundant number, since it is smaller than the sum of its proper divisors (34663632361880).

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

21113354364520 is a wasteful number, since it uses less digits than its factorization.

21113354364520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1161 (or 1157 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 40.

Adding to 21113354364520 its reverse (2546345331112), we get a palindrome (23659699695632).

The spelling of 21113354364520 in words is "twenty-one trillion, one hundred thirteen billion, three hundred fifty-four million, three hundred sixty-four thousand, five hundred twenty".