1861345 has 4 divisors (see below), whose sum is σ = 2233620. Its totient is φ = 1489072.

The previous prime is 1861339. The next prime is 1861351. The reversal of 1861345 is 5431681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5431681 = 173 ⋅31397.

It is an interprime number because it is at equal distance from previous prime (1861339) and next prime (1861351).

It can be written as a sum of positive squares in 2 ways, for example, as 1456849 + 404496 = 1207^2 + 636^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861345 - 2³ = 1861337 is a prime.

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, 186130 + ... + 186139.

It is an arithmetic number, because the mean of its divisors is an integer number (558405).

2^1861345 is an apocalyptic number.

It is an amenable number.

1861345 is a deficient number, since it is larger than the sum of its proper divisors (372275).

1861345 is an equidigital number, since it uses as much as digits as its factorization.

1861345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372274.

The product of its digits is 2880, while the sum is 28.

The square root of 1861345 is about 1364.3111815125. The cubic root of 1861345 is about 123.0105307484.

The spelling of 1861345 in words is "one million, eight hundred sixty-one thousand, three hundred forty-five".