1780489 has 2 divisors, whose sum is σ = 1780490. Its totient is φ = 1780488.

The previous prime is 1780487. The next prime is 1780517. The reversal of 1780489 is 9840871.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1776889 + 3600 = 1333^2 + 60^2 .

It is a cyclic number.

It is not a de Polignac number, because 1780489 - 2¹ = 1780487 is a prime.

Together with 1780487, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1780481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890244 + 890245.

It is an arithmetic number, because the mean of its divisors is an integer number (890245).

2^1780489 is an apocalyptic number.

It is an amenable number.

1780489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1780489 is an equidigital number, since it uses as much as digits as its factorization.

1780489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 1780489 is about 1334.3496543260. The cubic root of 1780489 is about 121.2029242978.

The spelling of 1780489 in words is "one million, seven hundred eighty thousand, four hundred eighty-nine".