644148 has 36 divisors (see below), whose sum is σ = 1687140. Its totient is φ = 206976.

The previous prime is 644143. The next prime is 644153. The reversal of 644148 is 841446.

644148 is a `hidden beast` number, since 644 + 14 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (644143) and next prime (644153).

It can be written as a sum of positive squares in 2 ways, for example, as 142884 + 501264 = 378^2 + 708^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644141) by changing a digit.

644148 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, 736 + ... + 1352.

It is an arithmetic number, because the mean of its divisors is an integer number (46865).

2⁶⁴⁴¹⁴⁸ 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 644148, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (843570).

644148 is an abundant number, since it is smaller than the sum of its proper divisors (1042992).

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

644148 is a wasteful number, since it uses less digits than its factorization.

644148 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 651 counting only the distinct ones).

The product of its digits is 3072, while the sum is 27.

The square root of 644148 is about 802.5883128977. The cubic root of 644148 is about 86.3631658834.

The spelling of 644148 in words is "six hundred forty-four thousand, one hundred forty-eight".