640887271 has 12 divisors (see below), whose sum is σ = 678036744. Its totient is φ = 605682000.

The previous prime is 640887259. The next prime is 640887283. The reversal of 640887271 is 172788046.

It is an interprime number because it is at equal distance from previous prime (640887259) and next prime (640887283).

It is a de Polignac number, because none of the positive numbers 2^k-640887271 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 (640887241) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164496 + ... + 168346.

It is an arithmetic number, because the mean of its divisors is an integer number (56503062).

Almost surely, 2^640887271 is an apocalyptic number.

640887271 is a deficient number, since it is larger than the sum of its proper divisors (37149473).

640887271 is a wasteful number, since it uses less digits than its factorization.

640887271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4350 (or 4331 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 43.

The square root of 640887271 is about 25315.7514405557. The cubic root of 640887271 is about 862.1719353310.

The spelling of 640887271 in words is "six hundred forty million, eight hundred eighty-seven thousand, two hundred seventy-one".