646799 has 4 divisors (see below), whose sum is σ = 684864. Its totient is φ = 608736.

The previous prime is 646781. The next prime is 646823. The reversal of 646799 is 997646.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 646799 - 2⁸ = 646543 is a prime.

It is a d-powerful number, because it can be written as 6² + 4⁸ + 7⁴ + 6⁶ + 9³ + 9⁶ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646099) 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, 19007 + ... + 19040.

It is an arithmetic number, because the mean of its divisors is an integer number (171216).

2⁶⁴⁶⁷⁹⁹ is an apocalyptic number.

646799 is a deficient number, since it is larger than the sum of its proper divisors (38065).

646799 is a wasteful number, since it uses less digits than its factorization.

646799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38064.

The product of its digits is 81648, while the sum is 41.

The square root of 646799 is about 804.2381488092. The cubic root of 646799 is about 86.4814799915.

The spelling of 646799 in words is "six hundred forty-six thousand, seven hundred ninety-nine".