6561161 has 2 divisors, whose sum is σ = 6561162. Its totient is φ = 6561160.

The previous prime is 6561151. The next prime is 6561193. The reversal of 6561161 is 1611656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6451600 + 109561 = 2540^2 + 331^2 .

It is a cyclic number.

It is not a de Polignac number, because 6561161 - 2⁶ = 6561097 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 6561161.

It is not a weakly prime, because it can be changed into another prime (6561151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280580 + 3280581.

It is an arithmetic number, because the mean of its divisors is an integer number (3280581).

Almost surely, 2^6561161 is an apocalyptic number.

It is an amenable number.

6561161 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561161 is an equidigital number, since it uses as much as digits as its factorization.

6561161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 26.

The square root of 6561161 is about 2561.4763321179. The cubic root of 6561161 is about 187.2090753538.

The spelling of 6561161 in words is "six million, five hundred sixty-one thousand, one hundred sixty-one".