644198 has 8 divisors (see below), whose sum is σ = 1023192. Its totient is φ = 303136.

The previous prime is 644197. The next prime is 644201. The reversal of 644198 is 891446.

644198 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 a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 9440 + ... + 9507.

It is an arithmetic number, because the mean of its divisors is an integer number (127899).

2⁶⁴⁴¹⁹⁸ is an apocalyptic number.

644198 is a deficient number, since it is larger than the sum of its proper divisors (378994).

644198 is a wasteful number, since it uses less digits than its factorization.

644198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18966.

The product of its digits is 6912, while the sum is 32.

The square root of 644198 is about 802.6194615134. The cubic root of 644198 is about 86.3654003837.

The spelling of 644198 in words is "six hundred forty-four thousand, one hundred ninety-eight".