13166551425521 has 4 divisors (see below), whose sum is σ = 14179363073652. Its totient is φ = 12153739777392.

The previous prime is 13166551425499. The next prime is 13166551425529. The reversal of 13166551425521 is 12552415566131.

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 8757391385521 + 4409160040000 = 2959289^2 + 2099800^2 .

It is a cyclic number.

It is not a de Polignac number, because 13166551425521 - 2¹⁸ = 13166551163377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13166551425529) 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, 506405824046 + ... + 506405824071.

It is an arithmetic number, because the mean of its divisors is an integer number (3544840768413).

Almost surely, 2^{13166551425521} is an apocalyptic number.

It is an amenable number.

13166551425521 is a deficient number, since it is larger than the sum of its proper divisors (1012811648131).

13166551425521 is a wasteful number, since it uses less digits than its factorization.

13166551425521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012811648130.

The product of its digits is 1080000, while the sum is 47.

The spelling of 13166551425521 in words is "thirteen trillion, one hundred sixty-six billion, five hundred fifty-one million, four hundred twenty-five thousand, five hundred twenty-one".