1921000 has 64 divisors (see below), whose sum is σ = 4801680. Its totient is φ = 716800.

The previous prime is 1920991. The next prime is 1921013. The reversal of 1921000 is 1291.

It can be written as a sum of positive squares in 8 ways, for example, as 4 + 1920996 = 2^2 + 1386^2 .

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 16944 + ... + 17056.

2^1921000 is an apocalyptic number.

1921000 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 1921000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2400840).

1921000 is an abundant number, since it is smaller than the sum of its proper divisors (2880680).

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

1921000 is a wasteful number, since it uses less digits than its factorization.

1921000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 13.

The square root of 1921000 is about 1386.0014430007. The cubic root of 1921000 is about 124.3108744966.

Adding to 1921000 its reverse (1291), we get a palindrome (1922291).

The spelling of 1921000 in words is "one million, nine hundred twenty-one thousand".