21115334625361 has 4 divisors (see below), whose sum is σ = 21115344667300. Its totient is φ = 21115324583424.

The previous prime is 21115334625337. The next prime is 21115334625487. The reversal of 21115334625361 is 16352643351112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 7030558310400 + 14084776314961 = 2651520^2 + 3752969^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21115334625361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21115334605361) 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, 524856 + ... + 6519673.

It is an arithmetic number, because the mean of its divisors is an integer number (5278836166825).

Almost surely, 2^{21115334625361} is an apocalyptic number.

It is an amenable number.

21115334625361 is a deficient number, since it is larger than the sum of its proper divisors (10041939).

21115334625361 is an equidigital number, since it uses as much as digits as its factorization.

21115334625361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10041938.

The product of its digits is 388800, while the sum is 43.

Adding to 21115334625361 its reverse (16352643351112), we get a palindrome (37467977976473).

The spelling of 21115334625361 in words is "twenty-one trillion, one hundred fifteen billion, three hundred thirty-four million, six hundred twenty-five thousand, three hundred sixty-one".