21500235555241 has 4 divisors (see below), whose sum is σ = 21905900377092. Its totient is φ = 21094570733392.

The previous prime is 21500235555157. The next prime is 21500235555263. The reversal of 21500235555241 is 14255553200512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15203292739600 + 6296942815641 = 3899140^2 + 2509371^2 .

It is a cyclic number.

It is not a de Polignac number, because 21500235555241 - 2²⁹ = 21499698684329 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21500235555194 and 21500235555203.

It is not an unprimeable number, because it can be changed into a prime (21500235555041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202832410846 + ... + 202832410951.

It is an arithmetic number, because the mean of its divisors is an integer number (5476475094273).

Almost surely, 2^{21500235555241} is an apocalyptic number.

It is an amenable number.

21500235555241 is a deficient number, since it is larger than the sum of its proper divisors (405664821851).

21500235555241 is an equidigital number, since it uses as much as digits as its factorization.

21500235555241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405664821850.

The product of its (nonzero) digits is 300000, while the sum is 40.

Adding to 21500235555241 its reverse (14255553200512), we get a palindrome (35755788755753).

The spelling of 21500235555241 in words is "twenty-one trillion, five hundred billion, two hundred thirty-five million, five hundred fifty-five thousand, two hundred forty-one".