640885213 has 2 divisors, whose sum is σ = 640885214. Its totient is φ = 640885212.

The previous prime is 640885211. The next prime is 640885249. The reversal of 640885213 is 312588046.

It is a happy number.

640885213 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 can be written as a sum of positive squares in only one way, i.e., 421193529 + 219691684 = 20523^2 + 14822^2 .

It is a cyclic number.

It is not a de Polignac number, because 640885213 - 2¹ = 640885211 is a prime.

Together with 640885211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640885211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320442606 + 320442607.

It is an arithmetic number, because the mean of its divisors is an integer number (320442607).

Almost surely, 2^640885213 is an apocalyptic number.

It is an amenable number.

640885213 is a deficient number, since it is larger than the sum of its proper divisors (1).

640885213 is an equidigital number, since it uses as much as digits as its factorization.

640885213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 640885213 is about 25315.7107938924. The cubic root of 640885213 is about 862.1710124689.

The spelling of 640885213 in words is "six hundred forty million, eight hundred eighty-five thousand, two hundred thirteen".