644055 has 8 divisors (see below), whose sum is σ = 1030512. Its totient is φ = 343488.

The previous prime is 644053. The next prime is 644057. The reversal of 644055 is 550446.

It is an interprime number because it is at equal distance from previous prime (644053) and next prime (644057).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644055 - 2¹ = 644053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21454 + ... + 21483.

It is an arithmetic number, because the mean of its divisors is an integer number (128814).

2⁶⁴⁴⁰⁵⁵ is an apocalyptic number.

644055 is a deficient number, since it is larger than the sum of its proper divisors (386457).

644055 is a wasteful number, since it uses less digits than its factorization.

644055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42945.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 644055 is about 802.5303732570. The cubic root of 644055 is about 86.3590094054.

The spelling of 644055 in words is "six hundred forty-four thousand, fifty-five".