640060656 has 20 divisors (see below), whose sum is σ = 1653490152. Its totient is φ = 213353536.

The previous prime is 640060649. The next prime is 640060697. The reversal of 640060656 is 656060046.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6667251 + ... + 6667346.

Almost surely, 2^640060656 is an apocalyptic number.

It is an amenable number.

640060656 is an abundant number, since it is smaller than the sum of its proper divisors (1013429496).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640060656 is a wasteful number, since it uses less digits than its factorization.

640060656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13334608 (or 13334602 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 640060656 is about 25299.4200724048. The cubic root of 640060656 is about 861.8011000258.

The spelling of 640060656 in words is "six hundred forty million, sixty thousand, six hundred fifty-six".