642817 has 8 divisors (see below), whose sum is σ = 741312. Its totient is φ = 546000.

The previous prime is 642809. The next prime is 642833. The reversal of 642817 is 718246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 642817 - 2³ = 642809 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 (642877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 567 + ... + 1267.

It is an arithmetic number, because the mean of its divisors is an integer number (92664).

2⁶⁴²⁸¹⁷ is an apocalyptic number.

It is an amenable number.

642817 is a deficient number, since it is larger than the sum of its proper divisors (98495).

642817 is a wasteful number, since it uses less digits than its factorization.

642817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839.

The product of its digits is 2688, while the sum is 28.

The square root of 642817 is about 801.7586918768. The cubic root of 642817 is about 86.3036409306.

The spelling of 642817 in words is "six hundred forty-two thousand, eight hundred seventeen".