644952 has 64 divisors (see below), whose sum is σ = 2016000. Its totient is φ = 167040.

The previous prime is 644951. The next prime is 644977. The reversal of 644952 is 259446.

644952 = T₃ + T₄ + ... + T₁₅₆.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1674 + ... + 2022.

It is an arithmetic number, because the mean of its divisors is an integer number (31500).

2⁶⁴⁴⁹⁵² 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 644952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1008000).

644952 is an abundant number, since it is smaller than the sum of its proper divisors (1371048).

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

644952 is a wasteful number, since it uses less digits than its factorization.

644952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376 (or 372 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 644952 is about 803.0890361598. The cubic root of 644952 is about 86.3990826377.

It can be divided in two parts, 644 and 952, that added together give a triangular number (1596 = T₅₆).

The spelling of 644952 in words is "six hundred forty-four thousand, nine hundred fifty-two".