640107505 has 4 divisors (see below), whose sum is σ = 768129012. Its totient is φ = 512086000.

The previous prime is 640107487. The next prime is 640107563. The reversal of 640107505 is 505701046.

640107505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 202293729 + 437813776 = 14223^2 + 20924^2 .

It is not a de Polignac number, because 640107505 - 2¹¹ = 640105457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64010746 + ... + 64010755.

It is an arithmetic number, because the mean of its divisors is an integer number (192032253).

Almost surely, 2^640107505 is an apocalyptic number.

It is an amenable number.

640107505 is a deficient number, since it is larger than the sum of its proper divisors (128021507).

640107505 is a wasteful number, since it uses less digits than its factorization.

640107505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128021506.

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 640107505 is about 25300.3459462514. The cubic root of 640107505 is about 861.8221259157.

The spelling of 640107505 in words is "six hundred forty million, one hundred seven thousand, five hundred five".