66601 has 2 divisors, whose sum is σ = 66602. Its totient is φ = 66600.

The previous prime is 66593. The next prime is 66617. The reversal of 66601 is 10666.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63001 + 3600 = 251^2 + 60^2 .

It is a cyclic number.

It is not a de Polignac number, because 66601 - 2³ = 66593 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33300 + 33301.

It is an arithmetic number, because the mean of its divisors is an integer number (33301).

2⁶⁶⁶⁰¹ is an apocalyptic number.

It is an amenable number.

66601 is a deficient number, since it is larger than the sum of its proper divisors (1).

66601 is an equidigital number, since it uses as much as digits as its factorization.

66601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 66601 is about 258.0716954647. The cubic root of 66601 is about 40.5346956659.

The spelling of 66601 in words is "sixty-six thousand, six hundred one".