1855891 has 2 divisors, whose sum is σ = 1855892. Its totient is φ = 1855890.

The previous prime is 1855853. The next prime is 1855921. The reversal of 1855891 is 1985581.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1855891 - 2¹⁵ = 1823123 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1855891.

It is not a weakly prime, because it can be changed into another prime (1855811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 927945 + 927946.

It is an arithmetic number, because the mean of its divisors is an integer number (927946).

2^1855891 is an apocalyptic number.

1855891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1855891 is an equidigital number, since it uses as much as digits as its factorization.

1855891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 37.

The square root of 1855891 is about 1362.3109043093. The cubic root of 1855891 is about 122.8902672150.

The spelling of 1855891 in words is "one million, eight hundred fifty-five thousand, eight hundred ninety-one".