666640256 has 32 divisors (see below), whose sum is σ = 1331967000. Its totient is φ = 332342784.

The previous prime is 666640243. The next prime is 666640259. The reversal of 666640256 is 652046666.

666640256 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666640259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37211 + ... + 52133.

Almost surely, 2^666640256 is an apocalyptic number.

It is an amenable number.

666640256 is a deficient number, since it is larger than the sum of its proper divisors (665326744).

666640256 is a wasteful number, since it uses less digits than its factorization.

666640256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15286 (or 15274 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 41.

The square root of 666640256 is about 25819.3775292899. The cubic root of 666640256 is about 873.5689286627.

The spelling of 666640256 in words is "six hundred sixty-six million, six hundred forty thousand, two hundred fifty-six".