640503351265 has 4 divisors (see below), whose sum is σ = 768604021524. Its totient is φ = 512402681008.

The previous prime is 640503351263. The next prime is 640503351269. The reversal of 640503351265 is 562153305046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 340896002769 + 299607348496 = 583863^2 + 547364^2 .

It is a cyclic number.

It is not a de Polignac number, because 640503351265 - 2¹ = 640503351263 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640503351263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64050335122 + ... + 64050335131.

It is an arithmetic number, because the mean of its divisors is an integer number (192151005381).

Almost surely, 2^640503351265 is an apocalyptic number.

It is an amenable number.

640503351265 is a deficient number, since it is larger than the sum of its proper divisors (128100670259).

640503351265 is a wasteful number, since it uses less digits than its factorization.

640503351265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128100670258.

The product of its (nonzero) digits is 324000, while the sum is 40.

The spelling of 640503351265 in words is "six hundred forty billion, five hundred three million, three hundred fifty-one thousand, two hundred sixty-five".