1921680 has 120 divisors (see below), whose sum is σ = 6876792. Its totient is φ = 479232.

The previous prime is 1921657. The next prime is 1921681. The reversal of 1921680 is 861291.

It can be written as a sum of positive squares in 4 ways, for example, as 242064 + 1679616 = 492^2 + 1296^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921681) 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, 12162 + ... + 12318.

2^1921680 is an apocalyptic number.

1921680 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 1921680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3438396).

1921680 is an abundant number, since it is smaller than the sum of its proper divisors (4955112).

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

1921680 is a wasteful number, since it uses less digits than its factorization.

1921680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1921680 is about 1386.2467312856. The cubic root of 1921680 is about 124.3255407160.

It can be divided in two parts, 1921 and 680, that added together give a square (2601 = 51²).

The spelling of 1921680 in words is "one million, nine hundred twenty-one thousand, six hundred eighty".