9721819800 has 768 divisors, whose sum is σ = 42340147200. Its totient is φ = 1991692800.

The previous prime is 9721819799. The next prime is 9721819823. The reversal of 9721819800 is 89181279.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 42827287 + ... + 42827513.

It is an arithmetic number, because the mean of its divisors is an integer number (55130400).

Almost surely, 2^9721819800 is an apocalyptic number.

9721819800 is a gapful number since it is divisible by the number (90) 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 9721819800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21170073600).

9721819800 is an abundant number, since it is smaller than the sum of its proper divisors (32618327400).

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

9721819800 is a wasteful number, since it uses less digits than its factorization.

9721819800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 358 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 45.

The square root of 9721819800 is about 98599.2890440900. The cubic root of 9721819800 is about 2134.2691602769.

The spelling of 9721819800 in words is "nine billion, seven hundred twenty-one million, eight hundred nineteen thousand, eight hundred".