19553840640 has 720 divisors, whose sum is σ = 76129221168. Its totient is φ = 4793499648.

The previous prime is 19553840611. The next prime is 19553840641. The reversal of 19553840640 is 4604835591.

19553840640 is a `hidden beast` number, since 19 + 5 + 538 + 40 + 64 + 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 (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19553840641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 454740459 + ... + 454740501.

Almost surely, 2^19553840640 is an apocalyptic number.

19553840640 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 19553840640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38064610584).

19553840640 is an abundant number, since it is smaller than the sum of its proper divisors (56575380528).

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

19553840640 is an frugal number, since it uses more digits than its factorization.

19553840640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 19553840640 in words is "nineteen billion, five hundred fifty-three million, eight hundred forty thousand, six hundred forty".