6640406 has 8 divisors (see below), whose sum is σ = 9977664. Its totient is φ = 3314520.

The previous prime is 6640397. The next prime is 6640409. The reversal of 6640406 is 6040466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640409) by changing a digit.

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, 1190 + ... + 3833.

It is an arithmetic number, because the mean of its divisors is an integer number (1247208).

Almost surely, 2^6640406 is an apocalyptic number.

6640406 is a deficient number, since it is larger than the sum of its proper divisors (3337258).

6640406 is a wasteful number, since it uses less digits than its factorization.

6640406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5686.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 6640406 is about 2576.8985234192. The cubic root of 6640406 is about 187.9597582496.

The spelling of 6640406 in words is "six million, six hundred forty thousand, four hundred six".