644195 has 8 divisors (see below), whose sum is σ = 813840. Its totient is φ = 488160.

The previous prime is 644191. The next prime is 644197. The reversal of 644195 is 591446.

644195 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 644195 - 2² = 644191 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644195.

It is not an unprimeable number, because it can be changed into a prime (644191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3296 + ... + 3485.

It is an arithmetic number, because the mean of its divisors is an integer number (101730).

644195 is a Friedman number, since it can be written as 4*(6+4+1)^5-9, using all its digits and the basic arithmetic operations.

2⁶⁴⁴¹⁹⁵ is an apocalyptic number.

644195 is a deficient number, since it is larger than the sum of its proper divisors (169645).

644195 is a wasteful number, since it uses less digits than its factorization.

644195 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6805.

The product of its digits is 4320, while the sum is 29.

The square root of 644195 is about 802.6175926305. The cubic root of 644195 is about 86.3652663169.

The spelling of 644195 in words is "six hundred forty-four thousand, one hundred ninety-five".