21115335120541 has 4 divisors (see below), whose sum is σ = 21115391164252. Its totient is φ = 21115279076832.

The previous prime is 21115335120533. The next prime is 21115335120557. The reversal of 21115335120541 is 14502153351112.

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 2326326552900 + 18789008567641 = 1525230^2 + 4334629^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115335120541 - 2³ = 21115335120533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21115335120497 and 21115335120506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115335160541) 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, 27452856 + ... + 28211521.

It is an arithmetic number, because the mean of its divisors is an integer number (5278847791063).

Almost surely, 2^{21115335120541} is an apocalyptic number.

It is an amenable number.

21115335120541 is a deficient number, since it is larger than the sum of its proper divisors (56043711).

21115335120541 is an equidigital number, since it uses as much as digits as its factorization.

21115335120541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56043710.

The product of its (nonzero) digits is 18000, while the sum is 34.

Adding to 21115335120541 its reverse (14502153351112), we get a palindrome (35617488471653).

The spelling of 21115335120541 in words is "twenty-one trillion, one hundred fifteen billion, three hundred thirty-five million, one hundred twenty thousand, five hundred forty-one".