645011779 has 2 divisors, whose sum is σ = 645011780. Its totient is φ = 645011778.

The previous prime is 645011737. The next prime is 645011813. The reversal of 645011779 is 977110546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645011779 - 2⁹ = 645011267 is a prime.

It is not a weakly prime, because it can be changed into another prime (645014779) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322505889 + 322505890.

It is an arithmetic number, because the mean of its divisors is an integer number (322505890).

Almost surely, 2^645011779 is an apocalyptic number.

645011779 is a deficient number, since it is larger than the sum of its proper divisors (1).

645011779 is an equidigital number, since it uses as much as digits as its factorization.

645011779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 645011779 is about 25397.0820961779. The cubic root of 645011779 is about 864.0175192742.

The spelling of 645011779 in words is "six hundred forty-five million, eleven thousand, seven hundred seventy-nine".