640317443 has 2 divisors, whose sum is σ = 640317444. Its totient is φ = 640317442.

The previous prime is 640317409. The next prime is 640317473. The reversal of 640317443 is 344713046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640317443 - 2¹⁰ = 640316419 is a prime.

It is not a weakly prime, because it can be changed into another prime (640317473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320158721 + 320158722.

It is an arithmetic number, because the mean of its divisors is an integer number (320158722).

Almost surely, 2^640317443 is an apocalyptic number.

640317443 is a deficient number, since it is larger than the sum of its proper divisors (1).

640317443 is an equidigital number, since it uses as much as digits as its factorization.

640317443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 32.

The square root of 640317443 is about 25304.4945217248. The cubic root of 640317443 is about 861.9163337561.

The spelling of 640317443 in words is "six hundred forty million, three hundred seventeen thousand, four hundred forty-three".