646680 has 64 divisors (see below), whose sum is σ = 2060640. Its totient is φ = 161792.

The previous prime is 646669. The next prime is 646687. The reversal of 646680 is 86646.

It is a happy number.

646680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1882 + ... + 2198.

2⁶⁴⁶⁶⁸⁰ is an apocalyptic number.

646680 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 646680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1030320).

646680 is an abundant number, since it is smaller than the sum of its proper divisors (1413960).

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

646680 is a wasteful number, since it uses less digits than its factorization.

646680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348 (or 344 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 646680 is about 804.1641623450. The cubic root of 646680 is about 86.4761759598.

It can be divided in two parts, 646 and 680, that added together give a triangular number (1326 = T₅₁).

The spelling of 646680 in words is "six hundred forty-six thousand, six hundred eighty".