1921830 has 48 divisors (see below), whose sum is σ = 4875120. Its totient is φ = 484288.

The previous prime is 1921823. The next prime is 1921841. The reversal of 1921830 is 381291.

It is an Ulam number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1921830.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40867 + ... + 40913.

It is an arithmetic number, because the mean of its divisors is an integer number (101565).

2^1921830 is an apocalyptic number.

1921830 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1921830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2437560).

1921830 is an abundant number, since it is smaller than the sum of its proper divisors (2953290).

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

1921830 is a wasteful number, since it uses less digits than its factorization.

1921830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 1921830 is about 1386.3008331527. The cubic root of 1921830 is about 124.3287754456.

The spelling of 1921830 in words is "one million, nine hundred twenty-one thousand, eight hundred thirty".