640331297 has 2 divisors, whose sum is σ = 640331298. Its totient is φ = 640331296.

The previous prime is 640331239. The next prime is 640331323. The reversal of 640331297 is 792133046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 447787921 + 192543376 = 21161^2 + 13876^2 .

It is a cyclic number.

It is not a de Polignac number, because 640331297 - 2¹⁸ = 640069153 is a prime.

It is not a weakly prime, because it can be changed into another prime (640331207) 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, 320165648 + 320165649.

It is an arithmetic number, because the mean of its divisors is an integer number (320165649).

Almost surely, 2^640331297 is an apocalyptic number.

It is an amenable number.

640331297 is a deficient number, since it is larger than the sum of its proper divisors (1).

640331297 is an equidigital number, since it uses as much as digits as its factorization.

640331297 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 35.

The square root of 640331297 is about 25304.7682660798. The cubic root of 640331297 is about 861.9225498931.

The spelling of 640331297 in words is "six hundred forty million, three hundred thirty-one thousand, two hundred ninety-seven".