640853 has 2 divisors, whose sum is σ = 640854. Its totient is φ = 640852.

The previous prime is 640847. The next prime is 640859. The reversal of 640853 is 358046.

It is a balanced prime because it is at equal distance from previous prime (640847) and next prime (640859).

It can be written as a sum of positive squares in only one way, i.e., 552049 + 88804 = 743^2 + 298^2 .

It is a cyclic number.

It is not a de Polignac number, because 640853 - 2⁴ = 640837 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640859) 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, 320426 + 320427.

It is an arithmetic number, because the mean of its divisors is an integer number (320427).

2⁶⁴⁰⁸⁵³ is an apocalyptic number.

It is an amenable number.

640853 is a deficient number, since it is larger than the sum of its proper divisors (1).

640853 is an equidigital number, since it uses as much as digits as its factorization.

640853 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 640853 is about 800.5329474794. The cubic root of 640853 is about 86.2156567043.

Adding to 640853 its reverse (358046), we get a palindrome (998899).

The spelling of 640853 in words is "six hundred forty thousand, eight hundred fifty-three".