1891291 has 2 divisors, whose sum is σ = 1891292. Its totient is φ = 1891290.

The previous prime is 1891283. The next prime is 1891297. The reversal of 1891291 is 1921981.

It is a strong prime.

It is an emirp because it is prime and its reverse (1921981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1891291 - 2³ = 1891283 is a prime.

It is not a weakly prime, because it can be changed into another prime (1891297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945645 + 945646.

It is an arithmetic number, because the mean of its divisors is an integer number (945646).

2^1891291 is an apocalyptic number.

1891291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891291 is an equidigital number, since it uses as much as digits as its factorization.

1891291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 31.

The square root of 1891291 is about 1375.2421604939. The cubic root of 1891291 is about 123.6667038003. Note that the first 3 decimals are identical.

The spelling of 1891291 in words is "one million, eight hundred ninety-one thousand, two hundred ninety-one".