644489522 has 16 divisors (see below), whose sum is σ = 994436352. Its totient is φ = 313138320.

The previous prime is 644489497. The next prime is 644489543. The reversal of 644489522 is 225984446.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21698 + ... + 41949.

It is an arithmetic number, because the mean of its divisors is an integer number (62152272).

Almost surely, 2^644489522 is an apocalyptic number.

644489522 is a deficient number, since it is larger than the sum of its proper divisors (349946830).

644489522 is a wasteful number, since it uses less digits than its factorization.

644489522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63793.

The product of its digits is 552960, while the sum is 44.

The square root of 644489522 is about 25386.7981833078. The cubic root of 644489522 is about 863.7842620148.

The spelling of 644489522 in words is "six hundred forty-four million, four hundred eighty-nine thousand, five hundred twenty-two".