21544550204245 has 8 divisors (see below), whose sum is σ = 25853770601784. Its totient is φ = 17235433258944.

The previous prime is 21544550204239. The next prime is 21544550204257. The reversal of 21544550204245 is 54240205544512.

It can be written as a sum of positive squares in 4 ways, for example, as 97657500004 + 21446892704241 = 312502^2 + 4631079^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21544550204245 - 2⁵ = 21544550204213 is a prime.

It is a super-4 number, since 4×21544550204245⁴ (a number of 54 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25404154 + ... + 26238523.

It is an arithmetic number, because the mean of its divisors is an integer number (3231721325223).

Almost surely, 2^{21544550204245} is an apocalyptic number.

It is an amenable number.

21544550204245 is a deficient number, since it is larger than the sum of its proper divisors (4309220397539).

21544550204245 is an equidigital number, since it uses as much as digits as its factorization.

21544550204245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51726119.

The product of its (nonzero) digits is 1280000, while the sum is 43.

Adding to 21544550204245 its reverse (54240205544512), we get a palindrome (75784755748757).

The spelling of 21544550204245 in words is "twenty-one trillion, five hundred forty-four billion, five hundred fifty million, two hundred four thousand, two hundred forty-five".