646807 has 4 divisors (see below), whose sum is σ = 739216. Its totient is φ = 554400.

The previous prime is 646781. The next prime is 646823. The reversal of 646807 is 708646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 708646 = 2 ⋅354323.

It is a de Polignac number, because none of the positive numbers 2^k-646807 is a prime.

It is a Duffinian number.

646807 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646837) 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, 46194 + ... + 46207.

It is an arithmetic number, because the mean of its divisors is an integer number (184804).

2⁶⁴⁶⁸⁰⁷ is an apocalyptic number.

646807 is a deficient number, since it is larger than the sum of its proper divisors (92409).

646807 is an equidigital number, since it uses as much as digits as its factorization.

646807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92408.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 646807 is about 804.2431224449. The cubic root of 646807 is about 86.4818365418.

The spelling of 646807 in words is "six hundred forty-six thousand, eight hundred seven".