6601561 has 2 divisors, whose sum is σ = 6601562. Its totient is φ = 6601560.

The previous prime is 6601549. The next prime is 6601601. The reversal of 6601561 is 1651066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6553600 + 47961 = 2560^2 + 219^2 .

It is a cyclic number.

It is not a de Polignac number, because 6601561 - 2⁷ = 6601433 is a prime.

It is not a weakly prime, because it can be changed into another prime (6601501) 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, 3300780 + 3300781.

It is an arithmetic number, because the mean of its divisors is an integer number (3300781).

Almost surely, 2^6601561 is an apocalyptic number.

It is an amenable number.

6601561 is a deficient number, since it is larger than the sum of its proper divisors (1).

6601561 is an equidigital number, since it uses as much as digits as its factorization.

6601561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 6601561 is about 2569.3503069842. The cubic root of 6601561 is about 187.5925326973.

The spelling of 6601561 in words is "six million, six hundred one thousand, five hundred sixty-one".