1555 has 4 divisors (see below), whose sum is σ = 1872.
Its totient is φ = 1240.
The previous prime is 1553. The next prime is 1559. The reversal of 1555 is 5551.
1555 is nontrivially palindromic in base 6.
It is a semiprime because it is the product of two primes.
It is not a de Polignac number, because 1555 - 21 = 1553 is a prime.
It is a nude number because it is divisible by every one of its digits.
It is a Duffinian number.
1555 is a modest number, since divided by 55 gives 15 as remainder.
1555 is a nontrivial repdigit in base 6.
It is a plaindrome in base 6 and base 10.
It is a nialpdrome in base 5, base 6 and base 12.
It is a zygodrome in base 6.
It is not an unprimeable number, because it can be changed into a prime (1553) by changing a digit.
It is a nontrivial repunit in base 6.
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 in 3 ways as a sum of consecutive naturals, for example, 151 + ... + 160.
It is an arithmetic number, because the mean of its divisors is an integer number (468).
1555 is a deficient number, since it is larger than the sum of its proper divisors (317).
1555 is an equidigital number, since it uses as much as digits as its factorization.
1555 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 316.
The product of its digits is 125, while the sum is 16.
The square root of 1555 is about 39.4334883063.
The cubic root of 1555 is about 11.5853759431.
The spelling of 1555 in words is "one thousand, five hundred fifty-five".