1780001 has 2 divisors, whose sum is σ = 1780002. Its totient is φ = 1780000.

The previous prime is 1779983. The next prime is 1780003. The reversal of 1780001 is 1000871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1600225 + 179776 = 1265^2 + 424^2 .

It is a cyclic number.

It is not a de Polignac number, because 1780001 - 2¹⁰ = 1778977 is a prime.

It is a Sophie Germain prime.

Together with 1780003, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1780003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890000 + 890001.

It is an arithmetic number, because the mean of its divisors is an integer number (890001).

2^1780001 is an apocalyptic number.

It is an amenable number.

1780001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1780001 is an equidigital number, since it uses as much as digits as its factorization.

1780001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 17.

The square root of 1780001 is about 1334.1667811784. The cubic root of 1780001 is about 121.1918501057.

Adding to 1780001 its reverse (1000871), we get a palindrome (2780872).

The spelling of 1780001 in words is "one million, seven hundred eighty thousand, one".