640508407 has 8 divisors (see below), whose sum is σ = 798556032. Its totient is φ = 499097400.

The previous prime is 640508399. The next prime is 640508417. The reversal of 640508407 is 704805046.

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 640508407 - 2³ = 640508399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640508417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4159069 + ... + 4159222.

It is an arithmetic number, because the mean of its divisors is an integer number (99819504).

Almost surely, 2^640508407 is an apocalyptic number.

640508407 is a deficient number, since it is larger than the sum of its proper divisors (158047625).

640508407 is a wasteful number, since it uses less digits than its factorization.

640508407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8318309.

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 640508407 is about 25308.2675622019. The cubic root of 640508407 is about 862.0020092976.

The spelling of 640508407 in words is "six hundred forty million, five hundred eight thousand, four hundred seven".