19817677920 has 576 divisors, whose sum is σ = 71447201280. Its totient is φ = 4602396672.

The previous prime is 19817677889. The next prime is 19817677927. The reversal of 19817677920 is 2977671891.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19817677927) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 192404589 + ... + 192404691.

It is an arithmetic number, because the mean of its divisors is an integer number (124040280).

Almost surely, 2^19817677920 is an apocalyptic number.

19817677920 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 19817677920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35723600640).

19817677920 is an abundant number, since it is smaller than the sum of its proper divisors (51629523360).

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

19817677920 is a wasteful number, since it uses less digits than its factorization.

19817677920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 2667168, while the sum is 57.

The spelling of 19817677920 in words is "nineteen billion, eight hundred seventeen million, six hundred seventy-seven thousand, nine hundred twenty".