1218815 has 16 divisors (see below), whose sum is σ = 1669248. Its totient is φ = 846336.

The previous prime is 1218787. The next prime is 1218821. The reversal of 1218815 is 5188121.

It is a Cunningham number, because it is equal to 1104²-1.

It is a cyclic number.

It is not a de Polignac number, because 1218815 - 2⁸ = 1218559 is a prime.

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 (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 554 + ... + 1656.

It is an arithmetic number, because the mean of its divisors is an integer number (104328).

2^1218815 is an apocalyptic number.

1218815 is a deficient number, since it is larger than the sum of its proper divisors (450433).

1218815 is a wasteful number, since it uses less digits than its factorization.

1218815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1138.

The product of its digits is 640, while the sum is 26.

The square root of 1218815 is about 1103.9995471014. Note that the first 3 decimals coincide. The cubic root of 1218815 is about 106.8183659681.

The spelling of 1218815 in words is "one million, two hundred eighteen thousand, eight hundred fifteen".