12061635561 has 20 divisors (see below), whose sum is σ = 18271782144. Its totient is φ = 7927831800.

The previous prime is 12061635557. The next prime is 12061635577. The reversal of 12061635561 is 16553616021.

12061635561 is a `hidden beast` number, since 1 + 2 + 0 + 61 + 6 + 35 + 561 = 666.

It is not a de Polignac number, because 12061635561 - 2² = 12061635557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12061635361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1042905 + ... + 1054406.

Almost surely, 2^12061635561 is an apocalyptic number.

It is an amenable number.

12061635561 is a deficient number, since it is larger than the sum of its proper divisors (6210146583).

12061635561 is an equidigital number, since it uses as much as digits as its factorization.

12061635561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2097394 (or 2097385 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 12061635561 in words is "twelve billion, sixty-one million, six hundred thirty-five thousand, five hundred sixty-one".