61156561 has 2 divisors, whose sum is σ = 61156562. Its totient is φ = 61156560.

The previous prime is 61156477. The next prime is 61156619. The reversal of 61156561 is 16565116.

61156561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60217600 + 938961 = 7760^2 + 969^2 .

It is a cyclic number.

It is not a de Polignac number, because 61156561 - 2⁹ = 61156049 is a prime.

It is not a weakly prime, because it can be changed into another prime (61156861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30578280 + 30578281.

It is an arithmetic number, because the mean of its divisors is an integer number (30578281).

Almost surely, 2^61156561 is an apocalyptic number.

It is an amenable number.

61156561 is a deficient number, since it is larger than the sum of its proper divisors (1).

61156561 is an equidigital number, since it uses as much as digits as its factorization.

61156561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 31.

The square root of 61156561 is about 7820.2660440678. The cubic root of 61156561 is about 393.9862076132.

The spelling of 61156561 in words is "sixty-one million, one hundred fifty-six thousand, five hundred sixty-one".