640963 has 2 divisors, whose sum is σ = 640964. Its totient is φ = 640962.

The previous prime is 640957. The next prime is 640967. The reversal of 640963 is 369046.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640963 is a prime.

It is an Ulam number.

640963 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (640967) 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, 320481 + 320482.

It is an arithmetic number, because the mean of its divisors is an integer number (320482).

2⁶⁴⁰⁹⁶³ is an apocalyptic number.

640963 is a deficient number, since it is larger than the sum of its proper divisors (1).

640963 is an equidigital number, since it uses as much as digits as its factorization.

640963 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 640963 is about 800.6016487617. The cubic root of 640963 is about 86.2205892861.

The spelling of 640963 in words is "six hundred forty thousand, nine hundred sixty-three".