646128 has 60 divisors (see below), whose sum is σ = 2069808. Its totient is φ = 184320.

The previous prime is 646103. The next prime is 646147. The reversal of 646128 is 821646.

646128 is a `hidden beast` number, since 646 + 12 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

646128 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 688 + ... + 1328.

2⁶⁴⁶¹²⁸ 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 646128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1034904).

646128 is an abundant number, since it is smaller than the sum of its proper divisors (1423680).

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

646128 is a wasteful number, since it uses less digits than its factorization.

646128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662 (or 653 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 646128 is about 803.8208755687. The cubic root of 646128 is about 86.4515638706.

It can be divided in two parts, 64612 and 8, that added together give a triangular number (64620 = T₃₅₉).

The spelling of 646128 in words is "six hundred forty-six thousand, one hundred twenty-eight".