646959 has 4 divisors (see below), whose sum is σ = 862616.
Its totient is φ = 431304.
The previous prime is 646957. The next prime is 646979. The reversal of 646959 is 959646.
It is a semiprime because it is the product of two primes.
It is not a de Polignac number, because 646959 - 21 = 646957 is a prime.
It is a D-number.
It is a Duffinian number.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646959.
It is not an unprimeable number, because it can be changed into a prime (646957) 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, 107824 + ... + 107829.
It is an arithmetic number, because the mean of its divisors is an integer number (215654).
2646959 is an apocalyptic number.
646959 is a deficient number, since it is larger than the sum of its proper divisors (215657).
646959 is a wasteful number, since it uses less digits than its factorization.
646959 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 215656.
The product of its digits is 58320, while the sum is 39.
The square root of 646959 is about 804.3376156814.
The cubic root of 646959 is about 86.4886104375.
The spelling of 646959 in words is "six hundred forty-six thousand, nine hundred fifty-nine".