1820705 has 4 divisors (see below), whose sum is σ = 2184852. Its totient is φ = 1456560.

The previous prime is 1820701. The next prime is 1820711. The reversal of 1820705 is 5070281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5070281 = 23 ⋅220447.

It can be written as a sum of positive squares in 2 ways, for example, as 976144 + 844561 = 988^2 + 919^2 .

It is not a de Polignac number, because 1820705 - 2² = 1820701 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 (1820701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182066 + ... + 182075.

It is an arithmetic number, because the mean of its divisors is an integer number (546213).

2^1820705 is an apocalyptic number.

It is an amenable number.

1820705 is a deficient number, since it is larger than the sum of its proper divisors (364147).

1820705 is an equidigital number, since it uses as much as digits as its factorization.

1820705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364146.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 1820705 is about 1349.3350214087. The cubic root of 1820705 is about 122.1086776841.

Adding to 1820705 its reverse (5070281), we get a palindrome (6890986).

The spelling of 1820705 in words is "one million, eight hundred twenty thousand, seven hundred five".