1216289 has 4 divisors (see below), whose sum is σ = 1258260. Its totient is φ = 1174320.

The previous prime is 1216277. The next prime is 1216337. The reversal of 1216289 is 9826121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9826121 = 83 ⋅118387.

It can be written as a sum of positive squares in 2 ways, for example, as 250000 + 966289 = 500^2 + 983^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216289 - 2⁴ = 1216273 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 41941 = 1216289 / (1 + 2 + 1 + 6 + 2 + 8 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20942 + ... + 20999.

It is an arithmetic number, because the mean of its divisors is an integer number (314565).

2^1216289 is an apocalyptic number.

It is an amenable number.

1216289 is a deficient number, since it is larger than the sum of its proper divisors (41971).

1216289 is an equidigital number, since it uses as much as digits as its factorization.

1216289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41970.

The product of its digits is 1728, while the sum is 29.

The square root of 1216289 is about 1102.8549315300. The cubic root of 1216289 is about 106.7445210694.

The spelling of 1216289 in words is "one million, two hundred sixteen thousand, two hundred eighty-nine".