5661665505161 has 2 divisors, whose sum is σ = 5661665505162. Its totient is φ = 5661665505160.

The previous prime is 5661665505143. The next prime is 5661665505163. The reversal of 5661665505161 is 1615055661665.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5560187580025 + 101477925136 = 2358005^2 + 318556^2 .

It is a cyclic number.

It is not a de Polignac number, because 5661665505161 - 2¹⁴ = 5661665488777 is a prime.

It is a super-2 number, since 2×5661665505161² (a number of 26 digits) contains 22 as substring.

Together with 5661665505163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (5661665505163) 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 as a sum of consecutive naturals, namely, 2830832752580 + 2830832752581.

It is an arithmetic number, because the mean of its divisors is an integer number (2830832752581).

Almost surely, 2^{5661665505161} is an apocalyptic number.

It is an amenable number.

5661665505161 is a deficient number, since it is larger than the sum of its proper divisors (1).

5661665505161 is an equidigital number, since it uses as much as digits as its factorization.

5661665505161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4860000, while the sum is 53.

The spelling of 5661665505161 in words is "five trillion, six hundred sixty-one billion, six hundred sixty-five million, five hundred five thousand, one hundred sixty-one".