640348897 has 2 divisors, whose sum is σ = 640348898. Its totient is φ = 640348896.

The previous prime is 640348879. The next prime is 640348921. The reversal of 640348897 is 798843046.

640348897 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with previous prime (640348879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 616230976 + 24117921 = 24824^2 + 4911^2 .

It is a cyclic number.

It is not a de Polignac number, because 640348897 - 2⁷ = 640348769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640348897.

It is not a weakly prime, because it can be changed into another prime (640348817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320174448 + 320174449.

It is an arithmetic number, because the mean of its divisors is an integer number (320174449).

Almost surely, 2^640348897 is an apocalyptic number.

It is an amenable number.

640348897 is a deficient number, since it is larger than the sum of its proper divisors (1).

640348897 is an equidigital number, since it uses as much as digits as its factorization.

640348897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1161216, while the sum is 49.

The square root of 640348897 is about 25305.1160242351. The cubic root of 640348897 is about 861.9304466896.

The spelling of 640348897 in words is "six hundred forty million, three hundred forty-eight thousand, eight hundred ninety-seven".