644396 has 12 divisors (see below), whose sum is σ = 1144080. Its totient is φ = 317520.

The previous prime is 644383. The next prime is 644401. The reversal of 644396 is 693446.

644396 = T₁₅ + T₁₆ + ... + T₁₅₆.

644396 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 851 + ... + 1418.

It is an arithmetic number, because the mean of its divisors is an integer number (95340).

2⁶⁴⁴³⁹⁶ is an apocalyptic number.

It is an amenable number.

644396 is a deficient number, since it is larger than the sum of its proper divisors (499684).

644396 is a wasteful number, since it uses less digits than its factorization.

644396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2344 (or 2342 counting only the distinct ones).

The product of its digits is 15552, while the sum is 32.

The square root of 644396 is about 802.7427981614. The cubic root of 644396 is about 86.3742478693.

The spelling of 644396 in words is "six hundred forty-four thousand, three hundred ninety-six".