1780813 has 6 divisors (see below), whose sum is σ = 1879854. Its totient is φ = 1686744.

The previous prime is 1780799. The next prime is 1780817. The reversal of 1780813 is 3180871.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1387684 + 393129 = 1178^2 + 627^2 .

It is not a de Polignac number, because 1780813 - 2⁹ = 1780301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1780817) 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 in 5 ways as a sum of consecutive naturals, for example, 2106 + ... + 2827.

It is an arithmetic number, because the mean of its divisors is an integer number (313309).

2^1780813 is an apocalyptic number.

It is an amenable number.

1780813 is a deficient number, since it is larger than the sum of its proper divisors (99041).

1780813 is an equidigital number, since it uses as much as digits as its factorization.

1780813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4971 (or 4952 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 1780813 is about 1334.4710562616. The cubic root of 1780813 is about 121.2102757175.

It can be divided in two parts, 178081 and 3, that added together give a square (178084 = 422²).

The spelling of 1780813 in words is "one million, seven hundred eighty thousand, eight hundred thirteen".