1211155 has 24 divisors (see below), whose sum is σ = 1700784. Its totient is φ = 820800.

The previous prime is 1211141. The next prime is 1211167. The reversal of 1211155 is 5511121.

It is not a de Polignac number, because 1211155 - 2⁷ = 1211027 is a prime.

It is an Ulam number.

It is a Duffinian number.

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 in 23 ways as a sum of consecutive naturals, for example, 19825 + ... + 19885.

It is an arithmetic number, because the mean of its divisors is an integer number (70866).

2^1211155 is an apocalyptic number.

1211155 is a deficient number, since it is larger than the sum of its proper divisors (489629).

1211155 is a wasteful number, since it uses less digits than its factorization.

1211155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 96 counting only the distinct ones).

The product of its digits is 50, while the sum is 16.

The square root of 1211155 is about 1100.5248747757. The cubic root of 1211155 is about 106.5941184200.

Adding to 1211155 its reverse (5511121), we get a palindrome (6722276).

The spelling of 1211155 in words is "one million, two hundred eleven thousand, one hundred fifty-five".