9721771776 has 216 divisors, whose sum is σ = 30316313664. Its totient is φ = 2984509440.

The previous prime is 9721771751. The next prime is 9721771777. The reversal of 9721771776 is 6771771279.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721771777) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1838256 + ... + 1843536.

It is an arithmetic number, because the mean of its divisors is an integer number (140353304).

Almost surely, 2^9721771776 is an apocalyptic number.

9721771776 is a gapful number since it is divisible by the number (96) 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 9721771776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15158156832).

9721771776 is an abundant number, since it is smaller than the sum of its proper divisors (20594541888).

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

9721771776 is a wasteful number, since it uses less digits than its factorization.

9721771776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5367 (or 5350 counting only the distinct ones).

The product of its digits is 1815156, while the sum is 54.

The square root of 9721771776 is about 98599.0455126215. The cubic root of 9721771776 is about 2134.2656459722.

The spelling of 9721771776 in words is "nine billion, seven hundred twenty-one million, seven hundred seventy-one thousand, seven hundred seventy-six".