644487063 has 16 divisors (see below), whose sum is σ = 937891200. Its totient is φ = 390408480.

The previous prime is 644487059. The next prime is 644487083. The reversal of 644487063 is 360784446.

It is not a de Polignac number, because 644487063 - 2² = 644487059 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644487083) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96393 + ... + 102861.

It is an arithmetic number, because the mean of its divisors is an integer number (58618200).

Almost surely, 2^644487063 is an apocalyptic number.

644487063 is a deficient number, since it is larger than the sum of its proper divisors (293404137).

644487063 is a wasteful number, since it uses less digits than its factorization.

644487063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9502.

The product of its (nonzero) digits is 387072, while the sum is 42.

The square root of 644487063 is about 25386.7497525776. The cubic root of 644487063 is about 863.7831634460.

The spelling of 644487063 in words is "six hundred forty-four million, four hundred eighty-seven thousand, sixty-three".