644948 has 6 divisors (see below), whose sum is σ = 1128666. Its totient is φ = 322472.

The previous prime is 644933. The next prime is 644951. The reversal of 644948 is 849446.

It can be written as a sum of positive squares in only one way, i.e., 386884 + 258064 = 622^2 + 508^2 .

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644948.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 80615 + ... + 80622.

It is an arithmetic number, because the mean of its divisors is an integer number (188111).

2⁶⁴⁴⁹⁴⁸ is an apocalyptic number.

It is an amenable number.

644948 is a deficient number, since it is larger than the sum of its proper divisors (483718).

644948 is a wasteful number, since it uses less digits than its factorization.

644948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161241 (or 161239 counting only the distinct ones).

The product of its digits is 27648, while the sum is 35.

The square root of 644948 is about 803.0865457720. The cubic root of 644948 is about 86.3989040213.

The spelling of 644948 in words is "six hundred forty-four thousand, nine hundred forty-eight".