644339061 has 24 divisors (see below), whose sum is σ = 962048256. Its totient is φ = 415134720.

The previous prime is 644339041. The next prime is 644339063. The reversal of 644339061 is 160933446.

644339061 is a `hidden beast` number, since 644 + 3 + 3 + 9 + 0 + 6 + 1 = 666.

It is not a de Polignac number, because 644339061 - 2⁵ = 644339029 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644339063) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 320686 + ... + 322688.

It is an arithmetic number, because the mean of its divisors is an integer number (40085344).

Almost surely, 2^644339061 is an apocalyptic number.

It is an amenable number.

644339061 is a deficient number, since it is larger than the sum of its proper divisors (317709195).

644339061 is a wasteful number, since it uses less digits than its factorization.

644339061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3193 (or 3190 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 644339061 is about 25383.8346393921. The cubic root of 644339061 is about 863.7170377726.

The spelling of 644339061 in words is "six hundred forty-four million, three hundred thirty-nine thousand, sixty-one".