1891321 has 4 divisors (see below), whose sum is σ = 1914192. Its totient is φ = 1868452.

The previous prime is 1891319. The next prime is 1891333. The reversal of 1891321 is 1231981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1891321 - 2¹ = 1891319 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1891361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11311 + ... + 11476.

It is an arithmetic number, because the mean of its divisors is an integer number (478548).

2^1891321 is an apocalyptic number.

It is an amenable number.

1891321 is a deficient number, since it is larger than the sum of its proper divisors (22871).

1891321 is an equidigital number, since it uses as much as digits as its factorization.

1891321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22870.

The product of its digits is 432, while the sum is 25.

The square root of 1891321 is about 1375.2530676206. The cubic root of 1891321 is about 123.6673576714.

The spelling of 1891321 in words is "one million, eight hundred ninety-one thousand, three hundred twenty-one".