19729405440 has 640 divisors, whose sum is σ = 75070195200. Its totient is φ = 4897013760.

The previous prime is 19729405387. The next prime is 19729405447. The reversal of 19729405440 is 4450492791.

19729405440 is a `hidden beast` number, since 19 + 7 + 2 + 94 + 0 + 544 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19729405447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 109002150 + ... + 109002330.

It is an arithmetic number, because the mean of its divisors is an integer number (117297180).

Almost surely, 2^19729405440 is an apocalyptic number.

19729405440 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 19729405440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37535097600).

19729405440 is an abundant number, since it is smaller than the sum of its proper divisors (55340789760).

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

19729405440 is a wasteful number, since it uses less digits than its factorization.

19729405440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 19729405440 in words is "nineteen billion, seven hundred twenty-nine million, four hundred five thousand, four hundred forty".