640970517 has 12 divisors (see below), whose sum is σ = 939384320. Its totient is φ = 388466760.

The previous prime is 640970503. The next prime is 640970531. The reversal of 640970517 is 715079046.

640970517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640970503) and next prime (640970531).

It is not a de Polignac number, because 640970517 - 2⁷ = 640970389 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 (640970717) 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, 882517 + ... + 883242.

Almost surely, 2^640970517 is an apocalyptic number.

It is an amenable number.

640970517 is a deficient number, since it is larger than the sum of its proper divisors (298413803).

640970517 is a wasteful number, since it uses less digits than its factorization.

640970517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1765784 (or 1765773 counting only the distinct ones).

The product of its (nonzero) digits is 52920, while the sum is 39.

The square root of 640970517 is about 25317.3955414059. The cubic root of 640970517 is about 862.2092634025.

The spelling of 640970517 in words is "six hundred forty million, nine hundred seventy thousand, five hundred seventeen".