640627565 has 8 divisors (see below), whose sum is σ = 768911640. Its totient is φ = 512396352.

The previous prime is 640627549. The next prime is 640627567. The reversal of 640627565 is 565726046.

It can be written as a sum of positive squares in 4 ways, for example, as 14577124 + 626050441 = 3818^2 + 25021^2 .

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 640627565 - 2⁴ = 640627549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640627567) 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, 21971 + ... + 41999.

It is an arithmetic number, because the mean of its divisors is an integer number (96113955).

Almost surely, 2^640627565 is an apocalyptic number.

It is an amenable number.

640627565 is a deficient number, since it is larger than the sum of its proper divisors (128284075).

640627565 is a wasteful number, since it uses less digits than its factorization.

640627565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26431.

The product of its (nonzero) digits is 302400, while the sum is 41.

The square root of 640627565 is about 25310.6215846233. The cubic root of 640627565 is about 862.0554606213.

The spelling of 640627565 in words is "six hundred forty million, six hundred twenty-seven thousand, five hundred sixty-five".