1915891 has 2 divisors, whose sum is σ = 1915892. Its totient is φ = 1915890.

The previous prime is 1915853. The next prime is 1915909. The reversal of 1915891 is 1985191.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1915891 - 2⁷ = 1915763 is a prime.

It is not a weakly prime, because it can be changed into another prime (1915811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 957945 + 957946.

It is an arithmetic number, because the mean of its divisors is an integer number (957946).

2^1915891 is an apocalyptic number.

1915891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1915891 is an equidigital number, since it uses as much as digits as its factorization.

1915891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 34.

The square root of 1915891 is about 1384.1571442578. The cubic root of 1915891 is about 124.2005728963.

The spelling of 1915891 in words is "one million, nine hundred fifteen thousand, eight hundred ninety-one".