666655061 has 2 divisors, whose sum is σ = 666655062. Its totient is φ = 666655060.

The previous prime is 666655057. The next prime is 666655063. The reversal of 666655061 is 160556666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 566154436 + 100500625 = 23794^2 + 10025^2 .

It is a cyclic number.

It is not a de Polignac number, because 666655061 - 2² = 666655057 is a prime.

Together with 666655063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666655063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333327530 + 333327531.

It is an arithmetic number, because the mean of its divisors is an integer number (333327531).

Almost surely, 2^666655061 is an apocalyptic number.

It is an amenable number.

666655061 is a deficient number, since it is larger than the sum of its proper divisors (1).

666655061 is an equidigital number, since it uses as much as digits as its factorization.

666655061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 666655061 is about 25819.6642309694. The cubic root of 666655061 is about 873.5753954650.

The spelling of 666655061 in words is "six hundred sixty-six million, six hundred fifty-five thousand, sixty-one".