644663063 has 8 divisors (see below), whose sum is σ = 703604496. Its totient is φ = 585777600.

The previous prime is 644663057. The next prime is 644663081. The reversal of 644663063 is 360366446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644663063 - 2⁶ = 644662999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644663003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12245 + ... + 37937.

It is an arithmetic number, because the mean of its divisors is an integer number (87950562).

Almost surely, 2^644663063 is an apocalyptic number.

644663063 is a deficient number, since it is larger than the sum of its proper divisors (58941433).

644663063 is a wasteful number, since it uses less digits than its factorization.

644663063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27985.

The product of its (nonzero) digits is 186624, while the sum is 38.

The square root of 644663063 is about 25390.2158911656. The cubic root of 644663063 is about 863.8617851432.

The spelling of 644663063 in words is "six hundred forty-four million, six hundred sixty-three thousand, sixty-three".