640253428237 has 2 divisors, whose sum is σ = 640253428238. Its totient is φ = 640253428236.

The previous prime is 640253428181. The next prime is 640253428247. The reversal of 640253428237 is 732824352046.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 607267967076 + 32985461161 = 779274^2 + 181619^2 .

It is a cyclic number.

It is not a de Polignac number, because 640253428237 - 2¹⁹ = 640252903949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640253428247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320126714118 + 320126714119.

It is an arithmetic number, because the mean of its divisors is an integer number (320126714119).

Almost surely, 2^640253428237 is an apocalyptic number.

It is an amenable number.

640253428237 is a deficient number, since it is larger than the sum of its proper divisors (1).

640253428237 is an equidigital number, since it uses as much as digits as its factorization.

640253428237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1935360, while the sum is 46.

The spelling of 640253428237 in words is "six hundred forty billion, two hundred fifty-three million, four hundred twenty-eight thousand, two hundred thirty-seven".