1921309 has 4 divisors (see below), whose sum is σ = 2069116. Its totient is φ = 1773504.

The previous prime is 1921307. The next prime is 1921319. The reversal of 1921309 is 9031291.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 850084 + 1071225 = 922^2 + 1035^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921309 - 2¹ = 1921307 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921307) 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 3 ways as a sum of consecutive naturals, for example, 73884 + ... + 73909.

It is an arithmetic number, because the mean of its divisors is an integer number (517279).

2^1921309 is an apocalyptic number.

It is an amenable number.

1921309 is a deficient number, since it is larger than the sum of its proper divisors (147807).

1921309 is a wasteful number, since it uses less digits than its factorization.

1921309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147806.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 1921309 is about 1386.1129102638. The cubic root of 1921309 is about 124.3175394282.

The spelling of 1921309 in words is "one million, nine hundred twenty-one thousand, three hundred nine".