21512540334305 has 4 divisors (see below), whose sum is σ = 25815048401172. Its totient is φ = 17210032267440.

The previous prime is 21512540334293. The next prime is 21512540334353. The reversal of 21512540334305 is 50343304521512.

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 13115689590481 + 8396850743824 = 3621559^2 + 2897732^2 .

It is not a de Polignac number, because 21512540334305 - 2⁸ = 21512540334049 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2151254033426 + ... + 2151254033435.

It is an arithmetic number, because the mean of its divisors is an integer number (6453762100293).

Almost surely, 2^{21512540334305} is an apocalyptic number.

It is an amenable number.

21512540334305 is a deficient number, since it is larger than the sum of its proper divisors (4302508066867).

21512540334305 is an equidigital number, since it uses as much as digits as its factorization.

21512540334305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4302508066866.

The product of its (nonzero) digits is 216000, while the sum is 38.

Adding to 21512540334305 its reverse (50343304521512), we get a palindrome (71855844855817).

The spelling of 21512540334305 in words is "twenty-one trillion, five hundred twelve billion, five hundred forty million, three hundred thirty-four thousand, three hundred five".