19915489440 has 720 divisors, whose sum is σ = 89224226784. Its totient is φ = 4136832000.

The previous prime is 19915489393. The next prime is 19915489441. The reversal of 19915489440 is 4498451991.

19915489440 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 548 + 94 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (19915489441) by changing a digit.

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 119 ways as a sum of consecutive naturals, for example, 6984015 + ... + 6986865.

Almost surely, 2^19915489440 is an apocalyptic number.

19915489440 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 19915489440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44612113392).

19915489440 is an abundant number, since it is smaller than the sum of its proper divisors (69308737344).

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

19915489440 is a wasteful number, since it uses less digits than its factorization.

19915489440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2903 (or 2879 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 19915489440 in words is "nineteen billion, nine hundred fifteen million, four hundred eighty-nine thousand, four hundred forty".