640417 has 4 divisors (see below), whose sum is σ = 642096. Its totient is φ = 638740.

The previous prime is 640411. The next prime is 640421. The reversal of 640417 is 714046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42 + ... + 1132.

It is an arithmetic number, because the mean of its divisors is an integer number (160524).

2⁶⁴⁰⁴¹⁷ is an apocalyptic number.

It is an amenable number.

640417 is a deficient number, since it is larger than the sum of its proper divisors (1679).

640417 is a wasteful number, since it uses less digits than its factorization.

640417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1678.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 640417 is about 800.2605825605. The cubic root of 640417 is about 86.1961001891.

The spelling of 640417 in words is "six hundred forty thousand, four hundred seventeen".