21715204406250 has 168 divisors, whose sum is σ = 54950894744544. Its totient is φ = 5720783300000.

The previous prime is 21715204406239. The next prime is 21715204406251. The reversal of 21715204406250 is 5260440251712.

It is a junction number, because it is equal to n+sod(n) for n = 21715204406199 and 21715204406208.

It is not an unprimeable number, because it can be changed into a prime (21715204406251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 645826939 + ... + 645860561.

Almost surely, 2^{21715204406250} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21715204406250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27475447372272).

21715204406250 is an abundant number, since it is smaller than the sum of its proper divisors (33235690338294).

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

21715204406250 is an frugal number, since it uses more digits than its factorization.

21715204406250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33824 (or 33716 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 39.

Adding to 21715204406250 its reverse (5260440251712), we get a palindrome (26975644657962).

The spelling of 21715204406250 in words is "twenty-one trillion, seven hundred fifteen billion, two hundred four million, four hundred six thousand, two hundred fifty".