644954849280 has 1152 divisors, whose sum is σ = 2705819074560. Its totient is φ = 142690222080.

The previous prime is 644954849263. The next prime is 644954849293. The reversal of 644954849280 is 82948459446.

644954849280 is a `hidden beast` number, since 6 + 4 + 4 + 9 + 548 + 4 + 9 + 2 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5078384577 + ... + 5078384703.

It is an arithmetic number, because the mean of its divisors is an integer number (2348801280).

Almost surely, 2^644954849280 is an apocalyptic number.

644954849280 is a gapful number since it is divisible by the number (60) 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 644954849280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1352909537280).

644954849280 is an abundant number, since it is smaller than the sum of its proper divisors (2060864225280).

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

644954849280 is an equidigital number, since it uses as much as digits as its factorization.

644954849280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 79626240, while the sum is 63.

The spelling of 644954849280 in words is "six hundred forty-four billion, nine hundred fifty-four million, eight hundred forty-nine thousand, two hundred eighty".