660041561 has 2 divisors, whose sum is σ = 660041562. Its totient is φ = 660041560.

The previous prime is 660041531. The next prime is 660041573. The reversal of 660041561 is 165140066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 501760000 + 158281561 = 22400^2 + 12581^2 .

It is a cyclic number.

It is not a de Polignac number, because 660041561 - 2⁶ = 660041497 is a prime.

It is a Chen prime.

It is equal to p_34288220 and since 660041561 and 34288220 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (660041521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330020780 + 330020781.

It is an arithmetic number, because the mean of its divisors is an integer number (330020781).

Almost surely, 2^660041561 is an apocalyptic number.

It is an amenable number.

660041561 is a deficient number, since it is larger than the sum of its proper divisors (1).

660041561 is an equidigital number, since it uses as much as digits as its factorization.

660041561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 660041561 is about 25691.2740244621. The cubic root of 660041561 is about 870.6770442131.

The spelling of 660041561 in words is "six hundred sixty million, forty-one thousand, five hundred sixty-one".