1001155 has 4 divisors (see below), whose sum is σ = 1201392. Its totient is φ = 800920.

The previous prime is 1001153. The next prime is 1001159. The reversal of 1001155 is 5511001.

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

It is not a de Polignac number, because 1001155 - 2¹ = 1001153 is a prime.

It is a super-2 number, since 2×1001155² = 2004622668050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1001153) by changing a digit.

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, 100111 + ... + 100120.

It is an arithmetic number, because the mean of its divisors is an integer number (300348).

2^1001155 is an apocalyptic number.

1001155 is a deficient number, since it is larger than the sum of its proper divisors (200237).

1001155 is an equidigital number, since it uses as much as digits as its factorization.

1001155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200236.

The product of its (nonzero) digits is 25, while the sum is 13.

The square root of 1001155 is about 1000.5773333431. The cubic root of 1001155 is about 100.0384851870.

Adding to 1001155 its reverse (5511001), we get a palindrome (6512156).

It can be divided in two parts, 1001 and 155, that added together give a square (1156 = 34²).

The spelling of 1001155 in words is "one million, one thousand, one hundred fifty-five".