644330 has 8 divisors (see below), whose sum is σ = 1159812. Its totient is φ = 257728.

The previous prime is 644327. The next prime is 644341. The reversal of 644330 is 33446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 638401 + 5929 = 799^2 + 77^2 .

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

It is a super-2 number, since 2×644330² = 830322297800, which contains 22 as substring.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32207 + ... + 32226.

2⁶⁴⁴³³⁰ is an apocalyptic number.

644330 is a deficient number, since it is larger than the sum of its proper divisors (515482).

644330 is a wasteful number, since it uses less digits than its factorization.

644330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64440.

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 644330 is about 802.7016880510. The cubic root of 644330 is about 86.3712989088.

Adding to 644330 its reverse (33446), we get a palindrome (677776).

The spelling of 644330 in words is "six hundred forty-four thousand, three hundred thirty".