644022459 has 12 divisors (see below), whose sum is σ = 962332800. Its totient is φ = 414543024.

The previous prime is 644022433. The next prime is 644022473. The reversal of 644022459 is 954220446.

644022459 is a `hidden beast` number, since 6 + 4 + 402 + 245 + 9 = 666.

It is not a de Polignac number, because 644022459 - 2¹² = 644018363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644022409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1233499 + ... + 1234020.

It is an arithmetic number, because the mean of its divisors is an integer number (80194400).

Almost surely, 2^644022459 is an apocalyptic number.

644022459 is a deficient number, since it is larger than the sum of its proper divisors (318310341).

644022459 is a wasteful number, since it uses less digits than its factorization.

644022459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2467554 (or 2467551 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 644022459 is about 25377.5975813315. The cubic root of 644022459 is about 863.5755494587.

The spelling of 644022459 in words is "six hundred forty-four million, twenty-two thousand, four hundred fifty-nine".