2117165005561 has 4 divisors (see below), whose sum is σ = 2140953376500. Its totient is φ = 2093376634624.

The previous prime is 2117165005531. The next prime is 2117165005589. The reversal of 2117165005561 is 1655005617112.

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 917112675600 + 1200052329961 = 957660^2 + 1095469^2 .

It is a cyclic number.

It is not a de Polignac number, because 2117165005561 - 2⁹ = 2117165005049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2117165005531) 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, 11894185336 + ... + 11894185513.

It is an arithmetic number, because the mean of its divisors is an integer number (535238344125).

Almost surely, 2^{2117165005561} is an apocalyptic number.

It is an amenable number.

2117165005561 is a deficient number, since it is larger than the sum of its proper divisors (23788370939).

2117165005561 is an equidigital number, since it uses as much as digits as its factorization.

2117165005561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23788370938.

The product of its (nonzero) digits is 63000, while the sum is 40.

The spelling of 2117165005561 in words is "two trillion, one hundred seventeen billion, one hundred sixty-five million, five thousand, five hundred sixty-one".