19643686920 has 768 divisors, whose sum is σ = 80223897600. Its totient is φ = 4242585600.

The previous prime is 19643686903. The next prime is 19643686927. The reversal of 19643686920 is 2968634691.

19643686920 is a `hidden beast` number, since 196 + 4 + 368 + 6 + 92 + 0 = 666.

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 (19643686927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 52663854 + ... + 52664226.

It is an arithmetic number, because the mean of its divisors is an integer number (104458200).

Almost surely, 2^19643686920 is an apocalyptic number.

19643686920 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 19643686920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40111948800).

19643686920 is an abundant number, since it is smaller than the sum of its proper divisors (60580210680).

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

19643686920 is a wasteful number, since it uses less digits than its factorization.

19643686920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 54.

The spelling of 19643686920 in words is "nineteen billion, six hundred forty-three million, six hundred eighty-six thousand, nine hundred twenty".