646464 has 112 divisors (see below), whose sum is σ = 2162048. Its totient is φ = 165888.

The previous prime is 646453. The next prime is 646519. The reversal of 646464 is 464646.

It is a tau number, because it is divible by the number of its divisors (112).

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

646464 is an undulating number in base 10.

Its product of digits (13824) is a multiple of the sum of its prime factors (72).

646464 is a modest number, since divided by 6464 gives 64 as remainder.

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 646464.

It is an unprimeable number.

646464 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is an upside-down number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17454 + ... + 17490.

It is an arithmetic number, because the mean of its divisors is an integer number (19304).

2⁶⁴⁶⁴⁶⁴ is an apocalyptic number.

646464 is a gapful number since it is divisible by the number (64) 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 646464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081024).

646464 is an abundant number, since it is smaller than the sum of its proper divisors (1515584).

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

646464 is a wasteful number, since it uses less digits than its factorization.

646464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72 (or 62 counting only the distinct ones).

The product of its digits is 13824, while the sum is 30.

The square root of 646464 is about 804.0298501921. The cubic root of 646464 is about 86.4665468109.

It can be divided in two parts, 6 and 46464, that multiplied together give a square (278784 = 528²).

The spelling of 646464 in words is "six hundred forty-six thousand, four hundred sixty-four".