644543286 has 16 divisors (see below), whose sum is σ = 1289855424. Its totient is φ = 214719624.

The previous prime is 644543281. The next prime is 644543311. The reversal of 644543286 is 682345446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644543281) 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, 20836 + ... + 41511.

It is an arithmetic number, because the mean of its divisors is an integer number (80615964).

Almost surely, 2^644543286 is an apocalyptic number.

644543286 is an abundant number, since it is smaller than the sum of its proper divisors (645312138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644543286 is a wasteful number, since it uses less digits than its factorization.

644543286 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64075.

The product of its digits is 552960, while the sum is 42.

The square root of 644543286 is about 25387.8570580504. The cubic root of 644543286 is about 863.8082806135.

The spelling of 644543286 in words is "six hundred forty-four million, five hundred forty-three thousand, two hundred eighty-six".