646560 has 72 divisors (see below), whose sum is σ = 2211300. Its totient is φ = 172032.

The previous prime is 646549. The next prime is 646571. The reversal of 646560 is 65646.

646560 is a `hidden beast` number, since 6 + 4 + 656 + 0 = 666.

646560 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (646549) and next prime (646571).

It can be written as a sum of positive squares in 2 ways, for example, as 646416 + 144 = 804^2 + 12^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1216 + ... + 1664.

2⁶⁴⁶⁵⁶⁰ is an apocalyptic number.

646560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1105650).

646560 is an abundant number, since it is smaller than the sum of its proper divisors (1564740).

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

646560 is a wasteful number, since it uses less digits than its factorization.

646560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 470 (or 459 counting only the distinct ones).

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

The square root of 646560 is about 804.0895472520. The cubic root of 646560 is about 86.4708266974.

The spelling of 646560 in words is "six hundred forty-six thousand, five hundred sixty".