66440761 has 2 divisors, whose sum is σ = 66440762. Its totient is φ = 66440760.

The previous prime is 66440741. The next prime is 66440771. The reversal of 66440761 is 16704466.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58982400 + 7458361 = 7680^2 + 2731^2 .

It is a cyclic number.

It is not a de Polignac number, because 66440761 - 2⁹ = 66440249 is a prime.

It is not a weakly prime, because it can be changed into another prime (66440741) 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, 33220380 + 33220381.

It is an arithmetic number, because the mean of its divisors is an integer number (33220381).

Almost surely, 2^66440761 is an apocalyptic number.

It is an amenable number.

66440761 is a deficient number, since it is larger than the sum of its proper divisors (1).

66440761 is an equidigital number, since it uses as much as digits as its factorization.

66440761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 66440761 is about 8151.1202297598. The cubic root of 66440761 is about 405.0216134378.

The spelling of 66440761 in words is "sixty-six million, four hundred forty thousand, seven hundred sixty-one".