640848449 has 2 divisors, whose sum is σ = 640848450. Its totient is φ = 640848448.

The previous prime is 640848437. The next prime is 640848469. The reversal of 640848449 is 944848046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 576960400 + 63888049 = 24020^2 + 7993^2 .

It is a cyclic number.

It is not a de Polignac number, because 640848449 - 2⁸ = 640848193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640848469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320424224 + 320424225.

It is an arithmetic number, because the mean of its divisors is an integer number (320424225).

Almost surely, 2^640848449 is an apocalyptic number.

It is an amenable number.

640848449 is a deficient number, since it is larger than the sum of its proper divisors (1).

640848449 is an equidigital number, since it uses as much as digits as its factorization.

640848449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 884736, while the sum is 47.

The square root of 640848449 is about 25314.9846731141. The cubic root of 640848449 is about 862.1545261774.

The spelling of 640848449 in words is "six hundred forty million, eight hundred forty-eight thousand, four hundred forty-nine".