6400668 has 12 divisors (see below), whose sum is σ = 14934920. Its totient is φ = 2133552.

The previous prime is 6400657. The next prime is 6400697. The reversal of 6400668 is 8660046.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266683 + ... + 266706.

Almost surely, 2^6400668 is an apocalyptic number.

It is an amenable number.

6400668 is an abundant number, since it is smaller than the sum of its proper divisors (8534252).

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

6400668 is a wasteful number, since it uses less digits than its factorization.

6400668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533396 (or 533394 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 6400668 is about 2529.9541497822. The cubic root of 6400668 is about 185.6700126642.

The spelling of 6400668 in words is "six million, four hundred thousand, six hundred sixty-eight".