644712 has 16 divisors (see below), whose sum is σ = 1611840. Its totient is φ = 214896.

The previous prime is 644701. The next prime is 644717. The reversal of 644712 is 217446.

644712 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 26863 = 644712 / (6 + 4 + 4 + 7 + 1 + 2).

It is not an unprimeable number, because it can be changed into a prime (644717) by changing a digit.

644712 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13408 + ... + 13455.

It is an arithmetic number, because the mean of its divisors is an integer number (100740).

2⁶⁴⁴⁷¹² is an apocalyptic number.

It is an amenable number.

644712 is an abundant number, since it is smaller than the sum of its proper divisors (967128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644712 is a wasteful number, since it uses less digits than its factorization.

644712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26872 (or 26868 counting only the distinct ones).

The product of its digits is 1344, while the sum is 24.

The square root of 644712 is about 802.9395992228. The cubic root of 644712 is about 86.3883643453.

The spelling of 644712 in words is "six hundred forty-four thousand, seven hundred twelve".