19644550560 has 144 divisors (see below), whose sum is σ = 67527028296. Its totient is φ = 5200257024.

The previous prime is 19644550507. The next prime is 19644550571. The reversal of 19644550560 is 6505544691.

19644550560 is a `hidden beast` number, since 1 + 9 + 6 + 44 + 550 + 56 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 18612599184 + 1031951376 = 136428^2 + 32124^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 23 ways as a sum of consecutive naturals, for example, 147492 + ... + 247068.

Almost surely, 2^19644550560 is an apocalyptic number.

19644550560 is a gapful number since it is divisible by the number (10) 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 19644550560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33763514148).

19644550560 is an abundant number, since it is smaller than the sum of its proper divisors (47882477736).

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

19644550560 is a wasteful number, since it uses less digits than its factorization.

19644550560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99735 (or 99724 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 45.

The spelling of 19644550560 in words is "nineteen billion, six hundred forty-four million, five hundred fifty thousand, five hundred sixty".