644734 has 8 divisors (see below), whose sum is σ = 970560. Its totient is φ = 321216.

The previous prime is 644731. The next prime is 644747. The reversal of 644734 is 437446.

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 (644731) 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 3 ways as a sum of consecutive naturals, for example, 622 + ... + 1294.

It is an arithmetic number, because the mean of its divisors is an integer number (121320).

2⁶⁴⁴⁷³⁴ is an apocalyptic number.

644734 is a deficient number, since it is larger than the sum of its proper divisors (325826).

644734 is a wasteful number, since it uses less digits than its factorization.

644734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1154.

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

The square root of 644734 is about 802.9532987665. The cubic root of 644734 is about 86.3893469662.

It can be divided in two parts, 644 and 734, that added together give a triangular number (1378 = T₅₂).

The spelling of 644734 in words is "six hundred forty-four thousand, seven hundred thirty-four".