640002806 has 8 divisors (see below), whose sum is σ = 960451320. Its totient is φ = 319852368.

The previous prime is 640002763. The next prime is 640002809. The reversal of 640002806 is 608200046.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640002809) 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, 69071 + ... + 77786.

It is an arithmetic number, because the mean of its divisors is an integer number (120056415).

Almost surely, 2^640002806 is an apocalyptic number.

640002806 is a deficient number, since it is larger than the sum of its proper divisors (320448514).

640002806 is a wasteful number, since it uses less digits than its factorization.

640002806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149038.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 640002806 is about 25298.2767397307. The cubic root of 640002806 is about 861.7751354575.

The spelling of 640002806 in words is "six hundred forty million, two thousand, eight hundred six".