19721246688 has 768 divisors, whose sum is σ = 73698508800. Its totient is φ = 5038848000.

The previous prime is 19721246687. The next prime is 19721246711. The reversal of 19721246688 is 88664212791.

It is a happy number.

19721246688 is a `hidden beast` number, since 1 + 97 + 2 + 12 + 466 + 88 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19721246683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 72771993 + ... + 72772263.

It is an arithmetic number, because the mean of its divisors is an integer number (95961600).

Almost surely, 2^19721246688 is an apocalyptic number.

19721246688 is a gapful number since it is divisible by the number (18) 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 19721246688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36849254400).

19721246688 is an abundant number, since it is smaller than the sum of its proper divisors (53977262112).

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

19721246688 is a wasteful number, since it uses less digits than its factorization.

19721246688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364 (or 350 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 54.

The spelling of 19721246688 in words is "nineteen billion, seven hundred twenty-one million, two hundred forty-six thousand, six hundred eighty-eight".