66440779 has 2 divisors, whose sum is σ = 66440780. Its totient is φ = 66440778.

The previous prime is 66440771. The next prime is 66440797. The reversal of 66440779 is 97704466.

Together with next prime (66440797) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66440779 - 2³ = 66440771 is a prime.

It is a super-2 number, since 2×66440779² = 8828754228253682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66440771) 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, 33220389 + 33220390.

It is an arithmetic number, because the mean of its divisors is an integer number (33220390).

Almost surely, 2^66440779 is an apocalyptic number.

66440779 is a deficient number, since it is larger than the sum of its proper divisors (1).

66440779 is an equidigital number, since it uses as much as digits as its factorization.

66440779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 43.

The square root of 66440779 is about 8151.1213339025. The cubic root of 66440779 is about 405.0216500137.

The spelling of 66440779 in words is "sixty-six million, four hundred forty thousand, seven hundred seventy-nine".