644705727 has 8 divisors (see below), whose sum is σ = 875826864. Its totient is φ = 421694208.

The previous prime is 644705707. The next prime is 644705749. The reversal of 644705727 is 727507446.

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

It is not a de Polignac number, because 644705727 - 2⁷ = 644705599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644705707) 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, 2027218 + ... + 2027535.

It is an arithmetic number, because the mean of its divisors is an integer number (109478358).

Almost surely, 2^644705727 is an apocalyptic number.

644705727 is a deficient number, since it is larger than the sum of its proper divisors (231121137).

644705727 is a wasteful number, since it uses less digits than its factorization.

644705727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4054809.

The product of its (nonzero) digits is 329280, while the sum is 42.

The square root of 644705727 is about 25391.0560434181. The cubic root of 644705727 is about 863.8808416025.

The spelling of 644705727 in words is "six hundred forty-four million, seven hundred five thousand, seven hundred twenty-seven".