644654360 has 64 divisors (see below), whose sum is σ = 1677715200. Its totient is φ = 218353536.

The previous prime is 644654333. The next prime is 644654371. The reversal of 644654360 is 63456446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 9371 + ... + 37109.

It is an arithmetic number, because the mean of its divisors is an integer number (26214300).

Almost surely, 2^644654360 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644654360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838857600).

644654360 is an abundant number, since it is smaller than the sum of its proper divisors (1033060840).

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

644654360 is a wasteful number, since it uses less digits than its factorization.

644654360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27840 (or 27836 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 38.

The square root of 644654360 is about 25390.0445056719. The cubic root of 644654360 is about 863.8578977259.

It can be divided in two parts, 6446 and 54360, that added together give a palindrome (60806).

The spelling of 644654360 in words is "six hundred forty-four million, six hundred fifty-four thousand, three hundred sixty".