640643635620253 has 12 divisors (see below), whose sum is σ = 657369368444160. Its totient is φ = 624332428812456.

The previous prime is 640643635620251. The next prime is 640643635620271. The reversal of 640643635620253 is 352026536346046.

It is not a de Polignac number, because 640643635620253 - 2¹ = 640643635620251 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640643635620194 and 640643635620203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640643635620251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 390243133 + ... + 391881346.

It is an arithmetic number, because the mean of its divisors is an integer number (54780780703680).

Almost surely, 2^{640643635620253} is an apocalyptic number.

It is an amenable number.

640643635620253 is a deficient number, since it is larger than the sum of its proper divisors (16725732823907).

640643635620253 is an equidigital number, since it uses as much as digits as its factorization.

640643635620253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 782125008 (or 782124965 counting only the distinct ones).

The product of its (nonzero) digits is 55987200, while the sum is 55.

The spelling of 640643635620253 in words is "six hundred forty trillion, six hundred forty-three billion, six hundred thirty-five million, six hundred twenty thousand, two hundred fifty-three".