644606241 has 4 divisors (see below), whose sum is σ = 859474992. Its totient is φ = 429737492.

The previous prime is 644606233. The next prime is 644606243. The reversal of 644606241 is 142606446.

644606241 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644606241 - 2³ = 644606233 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644606243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107434371 + ... + 107434376.

It is an arithmetic number, because the mean of its divisors is an integer number (214868748).

Almost surely, 2^644606241 is an apocalyptic number.

It is an amenable number.

644606241 is a deficient number, since it is larger than the sum of its proper divisors (214868751).

644606241 is a wasteful number, since it uses less digits than its factorization.

644606241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214868750.

The product of its (nonzero) digits is 27648, while the sum is 33.

The square root of 644606241 is about 25389.0968921701. The cubic root of 644606241 is about 863.8364035139.

The spelling of 644606241 in words is "six hundred forty-four million, six hundred six thousand, two hundred forty-one".