12171122166561 has 16 divisors (see below), whose sum is σ = 16265981082624. Its totient is φ = 8095181561424.

The previous prime is 12171122166547. The next prime is 12171122166571. The reversal of 12171122166561 is 16566122117121.

12171122166561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12171122166561 - 2¹⁷ = 12171122035489 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12171122166571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4143510 + ... + 6442896.

It is an arithmetic number, because the mean of its divisors is an integer number (1016623817664).

Almost surely, 2^{12171122166561} is an apocalyptic number.

It is an amenable number.

12171122166561 is a deficient number, since it is larger than the sum of its proper divisors (4094858916063).

12171122166561 is a wasteful number, since it uses less digits than its factorization.

12171122166561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2303500.

The product of its digits is 60480, while the sum is 42.

The spelling of 12171122166561 in words is "twelve trillion, one hundred seventy-one billion, one hundred twenty-two million, one hundred sixty-six thousand, five hundred sixty-one".