644473333 has 8 divisors (see below), whose sum is σ = 751572800. Its totient is φ = 552405420.

The previous prime is 644473327. The next prime is 644473339. The reversal of 644473333 is 333374446.

It is an interprime number because it is at equal distance from previous prime (644473327) and next prime (644473339).

It is not a de Polignac number, because 644473333 - 2¹³ = 644465141 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644473292 and 644473301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644473339) 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, 939123 + ... + 939808.

It is an arithmetic number, because the mean of its divisors is an integer number (93946600).

Almost surely, 2^644473333 is an apocalyptic number.

It is an amenable number.

644473333 is a deficient number, since it is larger than the sum of its proper divisors (107099467).

644473333 is an equidigital number, since it uses as much as digits as its factorization.

644473333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1878952 (or 1878938 counting only the distinct ones).

The product of its digits is 217728, while the sum is 37.

The square root of 644473333 is about 25386.4793344804. The cubic root of 644473333 is about 863.7770294583. Note that the first 3 decimals are identical.

The spelling of 644473333 in words is "six hundred forty-four million, four hundred seventy-three thousand, three hundred thirty-three".