640743565 has 32 divisors (see below), whose sum is σ = 960304896. Its totient is φ = 398722560.

The previous prime is 640743563. The next prime is 640743569. The reversal of 640743565 is 565347046.

It is not a de Polignac number, because 640743565 - 2¹ = 640743563 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640743563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 296529 + ... + 298681.

It is an arithmetic number, because the mean of its divisors is an integer number (30009528).

Almost surely, 2^640743565 is an apocalyptic number.

It is an amenable number.

640743565 is a deficient number, since it is larger than the sum of its proper divisors (319561331).

640743565 is a wasteful number, since it uses less digits than its factorization.

640743565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2949.

The product of its (nonzero) digits is 302400, while the sum is 40.

The square root of 640743565 is about 25312.9130089763. The cubic root of 640743565 is about 862.1074889780.

The spelling of 640743565 in words is "six hundred forty million, seven hundred forty-three thousand, five hundred sixty-five".