640630205 has 8 divisors (see below), whose sum is σ = 769240800. Its totient is φ = 512181136.

The previous prime is 640630187. The next prime is 640630223. The reversal of 640630205 is 502036046.

It is an interprime number because it is at equal distance from previous prime (640630187) and next prime (640630223).

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

It is a cyclic number.

It is not a de Polignac number, because 640630205 - 2¹⁰ = 640629181 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31475 + ... + 47664.

It is an arithmetic number, because the mean of its divisors is an integer number (96155100).

Almost surely, 2^640630205 is an apocalyptic number.

It is an amenable number.

640630205 is a deficient number, since it is larger than the sum of its proper divisors (128610595).

640630205 is a wasteful number, since it uses less digits than its factorization.

640630205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80763.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 640630205 is about 25310.6737365879. The cubic root of 640630205 is about 862.0566447847.

The spelling of 640630205 in words is "six hundred forty million, six hundred thirty thousand, two hundred five".