1921320000 has 350 divisors, whose sum is σ = 7128966438. Its totient is φ = 511488000.

The previous prime is 1921319993. The next prime is 1921320067. The reversal of 1921320000 is 231291.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 645973056 + 1275346944 = 25416^2 + 35712^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 49 ways as a sum of consecutive naturals, for example, 3239704 + ... + 3240296.

Almost surely, 2^1921320000 is an apocalyptic number.

1921320000 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 1921320000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3564483219).

1921320000 is an abundant number, since it is smaller than the sum of its proper divisors (5207646438).

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

1921320000 is an frugal number, since it uses more digits than its factorization.

1921320000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637 (or 603 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 1921320000 is about 43832.8643827893. The cubic root of 1921320000 is about 1243.1777667794.

Adding to 1921320000 its reverse (231291), we get a palindrome (1921551291).

The spelling of 1921320000 in words is "one billion, nine hundred twenty-one million, three hundred twenty thousand".