640434105765 has 16 divisors (see below), whose sum is σ = 1138549521600. Its totient is φ = 341564856336.

The previous prime is 640434105721. The next prime is 640434105809. The reversal of 640434105765 is 567501434046.

640434105765 is a `hidden beast` number, since 6 + 40 + 4 + 34 + 1 + 0 + 576 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (640434105721) and next prime (640434105809).

It is not a de Polignac number, because 640434105765 - 2¹¹ = 640434103717 is a prime.

It is a super-3 number, since 3×640434105765³ (a number of 36 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 640434105765.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2371978035 + ... + 2371978304.

It is an arithmetic number, because the mean of its divisors is an integer number (71159345100).

Almost surely, 2^640434105765 is an apocalyptic number.

It is an amenable number.

640434105765 is a deficient number, since it is larger than the sum of its proper divisors (498115415835).

640434105765 is a wasteful number, since it uses less digits than its factorization.

640434105765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4743956353 (or 4743956347 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 45.

The spelling of 640434105765 in words is "six hundred forty billion, four hundred thirty-four million, one hundred five thousand, seven hundred sixty-five".