646056 has 40 divisors (see below), whose sum is σ = 1811370. Its totient is φ = 215136.

The previous prime is 646039. The next prime is 646067. The reversal of 646056 is 650646.

It can be written as a sum of positive squares in only one way, i.e., 443556 + 202500 = 666^2 + 450^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

646056 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 150 + ... + 1146.

2⁶⁴⁶⁰⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (905685).

646056 is an abundant number, since it is smaller than the sum of its proper divisors (1165314).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646056 is a wasteful number, since it uses less digits than its factorization.

646056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015 (or 1002 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 646056 is about 803.7760882236. The cubic root of 646056 is about 86.4483525647.

The spelling of 646056 in words is "six hundred forty-six thousand, fifty-six".