640355899 has 2 divisors, whose sum is σ = 640355900. Its totient is φ = 640355898.

The previous prime is 640355897. The next prime is 640355923. The reversal of 640355899 is 998553046.

640355899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640355899 - 2¹ = 640355897 is a prime.

Together with 640355897, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640355897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320177949 + 320177950.

It is an arithmetic number, because the mean of its divisors is an integer number (320177950).

Almost surely, 2^640355899 is an apocalyptic number.

640355899 is a deficient number, since it is larger than the sum of its proper divisors (1).

640355899 is an equidigital number, since it uses as much as digits as its factorization.

640355899 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1166400, while the sum is 49.

The square root of 640355899 is about 25305.2543753269. The cubic root of 640355899 is about 861.9335883181.

The spelling of 640355899 in words is "six hundred forty million, three hundred fifty-five thousand, eight hundred ninety-nine".