644485289 has 24 divisors (see below), whose sum is σ = 766348128. Its totient is φ = 540294720.

The previous prime is 644485279. The next prime is 644485297. The reversal of 644485289 is 982584446.

It is not a de Polignac number, because 644485289 - 2⁸ = 644485033 is a prime.

It is a super-2 number, since 2×644485289² = 830722575474827042, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644485229) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 434429 + ... + 435909.

It is an arithmetic number, because the mean of its divisors is an integer number (31931172).

Almost surely, 2^644485289 is an apocalyptic number.

It is an amenable number.

644485289 is a deficient number, since it is larger than the sum of its proper divisors (121862839).

644485289 is a wasteful number, since it uses less digits than its factorization.

644485289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1685 (or 1678 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 50.

The square root of 644485289 is about 25386.7148130671. The cubic root of 644485289 is about 863.7823709021.

The spelling of 644485289 in words is "six hundred forty-four million, four hundred eighty-five thousand, two hundred eighty-nine".