1861205 has 4 divisors (see below), whose sum is σ = 2233452. Its totient is φ = 1488960.

The previous prime is 1861187. The next prime is 1861219. The reversal of 1861205 is 5021681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 894916 + 966289 = 946^2 + 983^2 .

It is not a de Polignac number, because 1861205 - 2⁶ = 1861141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 186116 + ... + 186125.

It is an arithmetic number, because the mean of its divisors is an integer number (558363).

2^1861205 is an apocalyptic number.

It is an amenable number.

1861205 is a deficient number, since it is larger than the sum of its proper divisors (372247).

1861205 is an equidigital number, since it uses as much as digits as its factorization.

1861205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372246.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 1861205 is about 1364.2598726049. The cubic root of 1861205 is about 123.0074466155.

Adding to 1861205 its reverse (5021681), we get a palindrome (6882886).

The spelling of 1861205 in words is "one million, eight hundred sixty-one thousand, two hundred five".