640665126 has 24 divisors (see below), whose sum is σ = 1439520264. Its totient is φ = 213554880.

The previous prime is 640665121. The next prime is 640665133. The reversal of 640665126 is 621566046.

It is a happy number.

640665126 is a `hidden beast` number, since 640 + 6 + 6 + 5 + 1 + 2 + 6 = 666.

640665126 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640665121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 658635 + ... + 659606.

It is an arithmetic number, because the mean of its divisors is an integer number (59980011).

Almost surely, 2^640665126 is an apocalyptic number.

640665126 is an abundant number, since it is smaller than the sum of its proper divisors (798855138).

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

640665126 is a wasteful number, since it uses less digits than its factorization.

640665126 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1318258 (or 1318246 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 640665126 is about 25311.3635744896. The cubic root of 640665126 is about 862.0723081804.

The spelling of 640665126 in words is "six hundred forty million, six hundred sixty-five thousand, one hundred twenty-six".