640302106021 has 2 divisors, whose sum is σ = 640302106022. Its totient is φ = 640302106020.

The previous prime is 640302106001. The next prime is 640302106061. The reversal of 640302106021 is 120601203046.

640302106021 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., 462007043521 + 178295062500 = 679711^2 + 422250^2 .

It is a cyclic number.

It is not a de Polignac number, because 640302106021 - 2¹⁵ = 640302073253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640302106001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320151053010 + 320151053011.

It is an arithmetic number, because the mean of its divisors is an integer number (320151053011).

Almost surely, 2^640302106021 is an apocalyptic number.

It is an amenable number.

640302106021 is a deficient number, since it is larger than the sum of its proper divisors (1).

640302106021 is an equidigital number, since it uses as much as digits as its factorization.

640302106021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 25.

Adding to 640302106021 its reverse (120601203046), we get a palindrome (760903309067).

The spelling of 640302106021 in words is "six hundred forty billion, three hundred two million, one hundred six thousand, twenty-one".