644622048 has 216 divisors, whose sum is σ = 2258710272. Its totient is φ = 173279232.

The previous prime is 644622019. The next prime is 644622059. The reversal of 644622048 is 840226446.

It is a happy number.

644622048 is a `hidden beast` number, since 6 + 446 + 2 + 204 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 35 ways as a sum of consecutive naturals, for example, 238561 + ... + 241247.

It is an arithmetic number, because the mean of its divisors is an integer number (10456992).

Almost surely, 2^644622048 is an apocalyptic number.

644622048 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644622048, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1129355136).

644622048 is an abundant number, since it is smaller than the sum of its proper divisors (1614088224).

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

644622048 is a wasteful number, since it uses less digits than its factorization.

644622048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2734 (or 2716 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 36.

The square root of 644622048 is about 25389.4081853044. The cubic root of 644622048 is about 863.8434644397.

The spelling of 644622048 in words is "six hundred forty-four million, six hundred twenty-two thousand, forty-eight".