644712893 has 8 divisors (see below), whose sum is σ = 703515360. Its totient is φ = 585942480.

The previous prime is 644712877. The next prime is 644712899. The reversal of 644712893 is 398217446.

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 644712893 - 2⁴ = 644712877 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 (644712899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57071 + ... + 67427.

It is an arithmetic number, because the mean of its divisors is an integer number (87939420).

Almost surely, 2^644712893 is an apocalyptic number.

It is an amenable number.

644712893 is a deficient number, since it is larger than the sum of its proper divisors (58802467).

644712893 is a wasteful number, since it uses less digits than its factorization.

644712893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16027.

The product of its digits is 290304, while the sum is 44.

The square root of 644712893 is about 25391.1971557073. The cubic root of 644712893 is about 863.8840423119.

It can be divided in two parts, 6447 and 12893, that multiplied together give a triangular number (83121171 = T₁₂₈₉₃).

The spelling of 644712893 in words is "six hundred forty-four million, seven hundred twelve thousand, eight hundred ninety-three".