640500871 has 4 divisors (see below), whose sum is σ = 647697600. Its totient is φ = 633304144.

The previous prime is 640500853. The next prime is 640500877. The reversal of 640500871 is 178005046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 178005046 = 2 ⋅89002523.

It is a cyclic number.

It is not a de Polignac number, because 640500871 - 2⁷ = 640500743 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 (640500877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3598231 + ... + 3598408.

It is an arithmetic number, because the mean of its divisors is an integer number (161924400).

Almost surely, 2^640500871 is an apocalyptic number.

640500871 is a deficient number, since it is larger than the sum of its proper divisors (7196729).

640500871 is an equidigital number, since it uses as much as digits as its factorization.

640500871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7196728.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 640500871 is about 25308.1186776102. The cubic root of 640500871 is about 861.9986286120.

The spelling of 640500871 in words is "six hundred forty million, five hundred thousand, eight hundred seventy-one".