640548565 has 8 divisors (see below), whose sum is σ = 776269368. Its totient is φ = 507364800.

The previous prime is 640548527. The next prime is 640548611. The reversal of 640548565 is 565845046.

It can be written as a sum of positive squares in 4 ways, for example, as 209612484 + 430936081 = 14478^2 + 20759^2 .

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

It is not a de Polignac number, because 640548565 - 2⁹ = 640548053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 633702 + ... + 634711.

It is an arithmetic number, because the mean of its divisors is an integer number (97033671).

Almost surely, 2^640548565 is an apocalyptic number.

It is an amenable number.

640548565 is a deficient number, since it is larger than the sum of its proper divisors (135720803).

640548565 is a wasteful number, since it uses less digits than its factorization.

640548565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1268519.

The product of its (nonzero) digits is 576000, while the sum is 43.

The square root of 640548565 is about 25309.0609268696. The cubic root of 640548565 is about 862.0200239210.

The spelling of 640548565 in words is "six hundred forty million, five hundred forty-eight thousand, five hundred sixty-five".