66756961 has 2 divisors, whose sum is σ = 66756962. Its totient is φ = 66756960.

The previous prime is 66756947. The next prime is 66757001. The reversal of 66756961 is 16965766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61779600 + 4977361 = 7860^2 + 2231^2 .

It is a cyclic number.

It is not a de Polignac number, because 66756961 - 2¹¹ = 66754913 is a prime.

It is not a weakly prime, because it can be changed into another prime (66756061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33378480 + 33378481.

It is an arithmetic number, because the mean of its divisors is an integer number (33378481).

Almost surely, 2^66756961 is an apocalyptic number.

It is an amenable number.

66756961 is a deficient number, since it is larger than the sum of its proper divisors (1).

66756961 is an equidigital number, since it uses as much as digits as its factorization.

66756961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 46.

The square root of 66756961 is about 8170.4933143599. The cubic root of 66756961 is about 405.6631132442.

The spelling of 66756961 in words is "sixty-six million, seven hundred fifty-six thousand, nine hundred sixty-one".