640137261329 has 8 divisors (see below), whose sum is σ = 645371236008. Its totient is φ = 634917928320.

The previous prime is 640137261319. The next prime is 640137261353. The reversal of 640137261329 is 923162731046.

It can be written as a sum of positive squares in 4 ways, for example, as 5449392400 + 634687868929 = 73820^2 + 796673^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640137261329 - 2⁸ = 640137261073 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640137261329.

It is not an unprimeable number, because it can be changed into a prime (640137261319) 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 7 ways as a sum of consecutive naturals, for example, 3572612 + ... + 3747509.

It is an arithmetic number, because the mean of its divisors is an integer number (80671404501).

Almost surely, 2^640137261329 is an apocalyptic number.

It is an amenable number.

640137261329 is a deficient number, since it is larger than the sum of its proper divisors (5233974679).

640137261329 is a wasteful number, since it uses less digits than its factorization.

640137261329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7320835.

The product of its (nonzero) digits is 326592, while the sum is 44.

The spelling of 640137261329 in words is "six hundred forty billion, one hundred thirty-seven million, two hundred sixty-one thousand, three hundred twenty-nine".