1921760640 has 256 divisors, whose sum is σ = 6895281600. Its totient is φ = 512096256.

The previous prime is 1921760629. The next prime is 1921760663. The reversal of 1921760640 is 460671291.

1921760640 is a `hidden beast` number, since 1 + 9 + 2 + 1 + 7 + 6 + 0 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 1921760595 and 1921760604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1398994 + ... + 1400366.

Almost surely, 2^1921760640 is an apocalyptic number.

1921760640 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 1921760640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3447640800).

1921760640 is an abundant number, since it is smaller than the sum of its proper divisors (4973520960).

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

1921760640 is an frugal number, since it uses more digits than its factorization.

1921760640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1413 (or 1383 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 1921760640 is about 43837.8904601944. The cubic root of 1921760640 is about 1243.2727972756.

The spelling of 1921760640 in words is "one billion, nine hundred twenty-one million, seven hundred sixty thousand, six hundred forty".