19770817920 has 384 divisors, whose sum is σ = 75684326400. Its totient is φ = 4372623360.

The previous prime is 19770817883. The next prime is 19770817921. The reversal of 19770817920 is 2971807791.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19770817921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2913091 + ... + 2919869.

It is an arithmetic number, because the mean of its divisors is an integer number (197094600).

Almost surely, 2^19770817920 is an apocalyptic number.

19770817920 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 19770817920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37842163200).

19770817920 is an abundant number, since it is smaller than the sum of its proper divisors (55913508480).

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

19770817920 is a wasteful number, since it uses less digits than its factorization.

19770817920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6846 (or 6827 counting only the distinct ones).

The product of its (nonzero) digits is 444528, while the sum is 51.

The spelling of 19770817920 in words is "nineteen billion, seven hundred seventy million, eight hundred seventeen thousand, nine hundred twenty".