1921721760 has 576 divisors, whose sum is σ = 8136640512. Its totient is φ = 418784256.

The previous prime is 1921721749. The next prime is 1921721761. The reversal of 1921721760 is 671271291.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1921721761) 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 95 ways as a sum of consecutive naturals, for example, 6259527 + ... + 6259833.

It is an arithmetic number, because the mean of its divisors is an integer number (14126112).

Almost surely, 2^1921721760 is an apocalyptic number.

1921721760 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 1921721760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4068320256).

1921721760 is an abundant number, since it is smaller than the sum of its proper divisors (6214918752).

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

1921721760 is a wasteful number, since it uses less digits than its factorization.

1921721760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 1921721760 is about 43837.4470059560. The cubic root of 1921721760 is about 1243.2644128162.

The spelling of 1921721760 in words is "one billion, nine hundred twenty-one million, seven hundred twenty-one thousand, seven hundred sixty".