640656065 has 8 divisors (see below), whose sum is σ = 878614080. Its totient is φ = 439306992.

The previous prime is 640656061. The next prime is 640656089. The reversal of 640656065 is 560656046.

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 640656065 - 2² = 640656061 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640656061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9152195 + ... + 9152264.

It is an arithmetic number, because the mean of its divisors is an integer number (109826760).

Almost surely, 2^640656065 is an apocalyptic number.

It is an amenable number.

640656065 is a deficient number, since it is larger than the sum of its proper divisors (237958015).

640656065 is a wasteful number, since it uses less digits than its factorization.

640656065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18304471.

The product of its (nonzero) digits is 129600, while the sum is 38.

The square root of 640656065 is about 25311.1845831048. The cubic root of 640656065 is about 862.0682440322.

The spelling of 640656065 in words is "six hundred forty million, six hundred fifty-six thousand, sixty-five".