1861166 has 4 divisors (see below), whose sum is σ = 2791752. Its totient is φ = 930582.

The previous prime is 1861157. The next prime is 1861187. The reversal of 1861166 is 6611681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6611681 = 29 ⋅227989.

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 as a sum of consecutive naturals, namely, 465290 + ... + 465293.

It is an arithmetic number, because the mean of its divisors is an integer number (697938).

2^1861166 is an apocalyptic number.

1861166 is a deficient number, since it is larger than the sum of its proper divisors (930586).

1861166 is an equidigital number, since it uses as much as digits as its factorization.

1861166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 930585.

The product of its digits is 1728, while the sum is 29.

The square root of 1861166 is about 1364.2455790656. The cubic root of 1861166 is about 123.0065874366.

The spelling of 1861166 in words is "one million, eight hundred sixty-one thousand, one hundred sixty-six".