1921685 has 12 divisors (see below), whose sum is σ = 2393508. Its totient is φ = 1481088.

The previous prime is 1921681. The next prime is 1921687. The reversal of 1921685 is 5861291.

It can be written as a sum of positive squares in 6 ways, for example, as 47524 + 1874161 = 218^2 + 1369^2 .

It is not a de Polignac number, because 1921685 - 2² = 1921681 is a prime.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

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

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3977 + ... + 4433.

It is an arithmetic number, because the mean of its divisors is an integer number (199459).

2^1921685 is an apocalyptic number.

It is an amenable number.

1921685 is a deficient number, since it is larger than the sum of its proper divisors (471823).

1921685 is an equidigital number, since it uses as much as digits as its factorization.

1921685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520 (or 491 counting only the distinct ones).

The product of its digits is 4320, while the sum is 32.

The square root of 1921685 is about 1386.2485347152. The cubic root of 1921685 is about 124.3256485430.

The spelling of 1921685 in words is "one million, nine hundred twenty-one thousand, six hundred eighty-five".