1858 has 4 divisors (see below), whose sum is σ = 2790.
Its totient is φ = 928.
The previous prime is 1847. The next prime is 1861. The reversal of 1858 is 8581.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in only one way, i.e., 1849 + 9 = 43^2 + 3^2
It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is an Ulam number.
It is an alternating number because its digits alternate between odd and even.
It is a plaindrome in base 6 and base 13.
It is a nialpdrome in base 16.
It is a congruent number.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 463 + ... + 466.
1858 is a deficient number, since it is larger than the sum of its proper divisors (932).
1858 is an equidigital number, since it uses as much as digits as its factorization.
1858 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 931.
The product of its digits is 320, while the sum is 22.
The square root of 1858 is about 43.1045241245.
The cubic root of 1858 is about 12.2936799664.
The spelling of 1858 in words is "one thousand, eight hundred fifty-eight".