19491388560 has 480 divisors, whose sum is σ = 79404739200. Its totient is φ = 4380687360.

The previous prime is 19491388547. The next prime is 19491388577. The reversal of 19491388560 is 6588319491.

19491388560 is a `hidden beast` number, since 1 + 9 + 49 + 1 + 38 + 8 + 560 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 19491388497 and 19491388506.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6454731 + ... + 6457749.

It is an arithmetic number, because the mean of its divisors is an integer number (165426540).

Almost surely, 2^19491388560 is an apocalyptic number.

19491388560 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 19491388560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39702369600).

19491388560 is an abundant number, since it is smaller than the sum of its proper divisors (59913350640).

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

19491388560 is a wasteful number, since it uses less digits than its factorization.

19491388560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3116 (or 3097 counting only the distinct ones).

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

The spelling of 19491388560 in words is "nineteen billion, four hundred ninety-one million, three hundred eighty-eight thousand, five hundred sixty".