640465020617 has 2 divisors, whose sum is σ = 640465020618. Its totient is φ = 640465020616.

The previous prime is 640465020599. The next prime is 640465020631. The reversal of 640465020617 is 716020564046.

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., 449475044041 + 190989976576 = 670429^2 + 437024^2 .

It is a cyclic number.

It is not a de Polignac number, because 640465020617 - 2⁶ = 640465020553 is a prime.

It is not a weakly prime, because it can be changed into another prime (640465020017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320232510308 + 320232510309.

It is an arithmetic number, because the mean of its divisors is an integer number (320232510309).

Almost surely, 2^640465020617 is an apocalyptic number.

It is an amenable number.

640465020617 is a deficient number, since it is larger than the sum of its proper divisors (1).

640465020617 is an equidigital number, since it uses as much as digits as its factorization.

640465020617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 640465020617 in words is "six hundred forty billion, four hundred sixty-five million, twenty thousand, six hundred seventeen".