12206635215521 has 4 divisors (see below), whose sum is σ = 12217563269652. Its totient is φ = 12195707161392.

The previous prime is 12206635215487. The next prime is 12206635215613. The reversal of 12206635215521 is 12551253660221.

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 7357439251600 + 4849195963921 = 2712460^2 + 2202089^2 .

It is a cyclic number.

It is not a de Polignac number, because 12206635215521 - 2³⁴ = 12189455346337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12206635215821) 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, 5464025390 + ... + 5464027623.

It is an arithmetic number, because the mean of its divisors is an integer number (3054390817413).

Almost surely, 2^{12206635215521} is an apocalyptic number.

It is an amenable number.

12206635215521 is a deficient number, since it is larger than the sum of its proper divisors (10928054131).

12206635215521 is a wasteful number, since it uses less digits than its factorization.

12206635215521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10928054130.

The product of its (nonzero) digits is 216000, while the sum is 41.

Adding to 12206635215521 its reverse (12551253660221), we get a palindrome (24757888875742).

The spelling of 12206635215521 in words is "twelve trillion, two hundred six billion, six hundred thirty-five million, two hundred fifteen thousand, five hundred twenty-one".