640636454513 has 24 divisors (see below), whose sum is σ = 706913327400. Its totient is φ = 580130369280.

The previous prime is 640636454483. The next prime is 640636454531. The reversal of 640636454513 is 315454636046.

It can be written as a sum of positive squares in 4 ways, for example, as 255235123264 + 385401331249 = 505208^2 + 620807^2 .

It is not a de Polignac number, because 640636454513 - 2¹⁸ = 640636192369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640636454543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 122983853 + ... + 122989061.

It is an arithmetic number, because the mean of its divisors is an integer number (29454721975).

Almost surely, 2^640636454513 is an apocalyptic number.

It is an amenable number.

640636454513 is a deficient number, since it is larger than the sum of its proper divisors (66276872887).

640636454513 is a wasteful number, since it uses less digits than its factorization.

640636454513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8993 (or 8982 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 47.

The spelling of 640636454513 in words is "six hundred forty billion, six hundred thirty-six million, four hundred fifty-four thousand, five hundred thirteen".