644652 has 48 divisors (see below), whose sum is σ = 1720320. Its totient is φ = 208656.

The previous prime is 644647. The next prime is 644653. The reversal of 644652 is 256446.

It is a happy number.

644652 is a `hidden beast` number, since 6 + 4 + 4 + 652 = 666.

644652 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×644652² = 831152402208, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (644653) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5013 + ... + 5139.

It is an arithmetic number, because the mean of its divisors is an integer number (35840).

2⁶⁴⁴⁶⁵² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644652, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (860160).

644652 is an abundant number, since it is smaller than the sum of its proper divisors (1075668).

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

644652 is a wasteful number, since it uses less digits than its factorization.

644652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 179 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 644652 is about 802.9022356427. The cubic root of 644652 is about 86.3856843566.

It can be divided in two parts, 644 and 652, that added together give a 4-th power (1296 = 6⁴).

The spelling of 644652 in words is "six hundred forty-four thousand, six hundred fifty-two".