1781089 has 2 divisors, whose sum is σ = 1781090. Its totient is φ = 1781088.

The previous prime is 1781063. The next prime is 1781099. The reversal of 1781089 is 9801871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1710864 + 70225 = 1308^2 + 265^2 .

It is a cyclic number.

It is not a de Polignac number, because 1781089 - 2⁵ = 1781057 is a prime.

It is not a weakly prime, because it can be changed into another prime (1781009) 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, 890544 + 890545.

It is an arithmetic number, because the mean of its divisors is an integer number (890545).

2^1781089 is an apocalyptic number.

It is an amenable number.

1781089 is a deficient number, since it is larger than the sum of its proper divisors (1).

1781089 is an equidigital number, since it uses as much as digits as its factorization.

1781089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 34.

The square root of 1781089 is about 1334.5744640147. The cubic root of 1781089 is about 121.2165373347.

It can be divided in two parts, 17810 and 89, that multiplied together give a triangular number (1585090 = T₁₇₈₀).

The spelling of 1781089 in words is "one million, seven hundred eighty-one thousand, eighty-nine".