21500503155040 has 576 divisors, whose sum is σ = 65205143410176. Its totient is φ = 6555082899456.

The previous prime is 21500503155031. The next prime is 21500503155041. The reversal of 21500503155040 is 4055130500512.

It is a junction number, because it is equal to n+sod(n) for n = 21500503154993 and 21500503155011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500503155041) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 594131827 + ... + 594168013.

It is an arithmetic number, because the mean of its divisors is an integer number (113203373976).

Almost surely, 2^{21500503155040} is an apocalyptic number.

21500503155040 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 21500503155040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32602571705088).

21500503155040 is an abundant number, since it is smaller than the sum of its proper divisors (43704640255136).

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

21500503155040 is a wasteful number, since it uses less digits than its factorization.

21500503155040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36351 (or 36330 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 31.

Adding to 21500503155040 its reverse (4055130500512), we get a palindrome (25555633655552).

The spelling of 21500503155040 in words is "twenty-one trillion, five hundred billion, five hundred three million, one hundred fifty-five thousand, forty".