1218155 has 4 divisors (see below), whose sum is σ = 1461792. Its totient is φ = 974520.

The previous prime is 1218131. The next prime is 1218157. The reversal of 1218155 is 5518121.

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

It is not a de Polignac number, because 1218155 - 2⁸ = 1217899 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1218155.

It is not an unprimeable number, because it can be changed into a prime (1218157) 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, 121811 + ... + 121820.

It is an arithmetic number, because the mean of its divisors is an integer number (365448).

2^1218155 is an apocalyptic number.

1218155 is a deficient number, since it is larger than the sum of its proper divisors (243637).

1218155 is an equidigital number, since it uses as much as digits as its factorization.

1218155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243636.

The product of its digits is 400, while the sum is 23.

The square root of 1218155 is about 1103.7005934582. The cubic root of 1218155 is about 106.7990814306.

The spelling of 1218155 in words is "one million, two hundred eighteen thousand, one hundred fifty-five".