644347 has 8 divisors (see below), whose sum is σ = 740160. Its totient is φ = 554760.

The previous prime is 644341. The next prime is 644353. The reversal of 644347 is 743446.

It is an interprime number because it is at equal distance from previous prime (644341) and next prime (644353).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644347 is a prime.

It is a Duffinian number.

644347 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (644341) 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, 1333 + ... + 1750.

It is an arithmetic number, because the mean of its divisors is an integer number (92520).

2⁶⁴⁴³⁴⁷ is an apocalyptic number.

644347 is a deficient number, since it is larger than the sum of its proper divisors (95813).

644347 is a wasteful number, since it uses less digits than its factorization.

644347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3113.

The product of its digits is 8064, while the sum is 28.

The square root of 644347 is about 802.7122772202. The cubic root of 644347 is about 86.3720585088.

Subtracting 644347 from its reverse (743446), we obtain a palindrome (99099).

The spelling of 644347 in words is "six hundred forty-four thousand, three hundred forty-seven".