12815527517 has 4 divisors (see below), whose sum is σ = 13801337340. Its totient is φ = 11829717696.

The previous prime is 12815527471. The next prime is 12815527559. The reversal of 12815527517 is 71572551821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71572551821 = 907 ⋅78911303.

It can be written as a sum of positive squares in 2 ways, for example, as 6401760121 + 6413767396 = 80011^2 + 80086^2 .

It is a cyclic number.

It is not a de Polignac number, because 12815527517 - 2¹² = 12815523421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12815527567) 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, 492904892 + ... + 492904917.

It is an arithmetic number, because the mean of its divisors is an integer number (3450334335).

Almost surely, 2^12815527517 is an apocalyptic number.

It is an amenable number.

12815527517 is a deficient number, since it is larger than the sum of its proper divisors (985809823).

12815527517 is an equidigital number, since it uses as much as digits as its factorization.

12815527517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 985809822.

The product of its digits is 196000, while the sum is 44.

The spelling of 12815527517 in words is "twelve billion, eight hundred fifteen million, five hundred twenty-seven thousand, five hundred seventeen".