644031 has 10 divisors (see below), whose sum is σ = 962192. Its totient is φ = 429300.

The previous prime is 644029. The next prime is 644047. The reversal of 644031 is 130446.

It is not a de Polignac number, because 644031 - 2¹ = 644029 is a prime.

It is a super-2 number, since 2×644031² = 829551857922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643995 and 644013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644051) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3895 + ... + 4056.

2⁶⁴⁴⁰³¹ is an apocalyptic number.

644031 is a deficient number, since it is larger than the sum of its proper divisors (318161).

644031 is an equidigital number, since it uses as much as digits as its factorization.

644031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7963 (or 7954 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 644031 is about 802.5154204126. The cubic root of 644031 is about 86.3579367010.

Adding to 644031 its reverse (130446), we get a palindrome (774477).

It can be divided in two parts, 64 and 4031, that added together give a triangular number (4095 = T₉₀).

The spelling of 644031 in words is "six hundred forty-four thousand, thirty-one".