640308479 has 8 divisors (see below), whose sum is σ = 644114592. Its totient is φ = 636513280.

The previous prime is 640308467. The next prime is 640308497. The reversal of 640308479 is 974803046.

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 640308479 - 2²⁰ = 639259903 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 (640308419) 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, 134687 + ... + 139359.

It is an arithmetic number, because the mean of its divisors is an integer number (80514324).

Almost surely, 2^640308479 is an apocalyptic number.

640308479 is a deficient number, since it is larger than the sum of its proper divisors (3806113).

640308479 is a wasteful number, since it uses less digits than its factorization.

640308479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5457.

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 640308479 is about 25304.3173984204. The cubic root of 640308479 is about 861.9123116605.

The spelling of 640308479 in words is "six hundred forty million, three hundred eight thousand, four hundred seventy-nine".