644982 has 16 divisors (see below), whose sum is σ = 1389360. Its totient is φ = 198432.

The previous prime is 644977. The next prime is 644999. The reversal of 644982 is 289446.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

644982 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 4057 + ... + 4212.

It is an arithmetic number, because the mean of its divisors is an integer number (86835).

2⁶⁴⁴⁹⁸² is an apocalyptic number.

644982 is an abundant number, since it is smaller than the sum of its proper divisors (744378).

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

644982 is a wasteful number, since it uses less digits than its factorization.

644982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8287.

The product of its digits is 13824, while the sum is 33.

The square root of 644982 is about 803.1077138218. The cubic root of 644982 is about 86.4004222373.

The spelling of 644982 in words is "six hundred forty-four thousand, nine hundred eighty-two".