1891489 has 2 divisors, whose sum is σ = 1891490. Its totient is φ = 1891488.

The previous prime is 1891457. The next prime is 1891499. The reversal of 1891489 is 9841981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1710864 + 180625 = 1308^2 + 425^2 .

It is a cyclic number.

It is not a de Polignac number, because 1891489 - 2⁵ = 1891457 is a prime.

It is not a weakly prime, because it can be changed into another prime (1891429) 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 as a sum of consecutive naturals, namely, 945744 + 945745.

It is an arithmetic number, because the mean of its divisors is an integer number (945745).

2^1891489 is an apocalyptic number.

It is an amenable number.

1891489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891489 is an equidigital number, since it uses as much as digits as its factorization.

1891489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 40.

The square root of 1891489 is about 1375.3141459318. The cubic root of 1891489 is about 123.6710192217.

The spelling of 1891489 in words is "one million, eight hundred ninety-one thousand, four hundred eighty-nine".