646406 has 8 divisors (see below), whose sum is σ = 993384. Its totient is φ = 315280.

The previous prime is 646403. The next prime is 646411. The reversal of 646406 is 604646.

646406 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a Curzon 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 646406.

It is not an unprimeable number, because it can be changed into a prime (646403) 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, 3860 + ... + 4023.

It is an arithmetic number, because the mean of its divisors is an integer number (124173).

2⁶⁴⁶⁴⁰⁶ is an apocalyptic number.

646406 is a deficient number, since it is larger than the sum of its proper divisors (346978).

646406 is a wasteful number, since it uses less digits than its factorization.

646406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7926.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 646406 is about 803.9937810705. The cubic root of 646406 is about 86.4639608408.

It can be divided in two parts, 64640 and 6, that added together give a palindrome (64646).

The spelling of 646406 in words is "six hundred forty-six thousand, four hundred six".