1216643 has 4 divisors (see below), whose sum is σ = 1219368. Its totient is φ = 1213920.

The previous prime is 1216619. The next prime is 1216681. The reversal of 1216643 is 3466121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3466121 = 1289 ⋅2689.

It is a cyclic number.

It is not a de Polignac number, because 1216643 - 2⁸ = 1216387 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 518 + ... + 1643.

It is an arithmetic number, because the mean of its divisors is an integer number (304842).

2^1216643 is an apocalyptic number.

1216643 is a deficient number, since it is larger than the sum of its proper divisors (2725).

1216643 is an equidigital number, since it uses as much as digits as its factorization.

1216643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2724.

The product of its digits is 864, while the sum is 23.

The square root of 1216643 is about 1103.0154124037. The cubic root of 1216643 is about 106.7548760358.

The spelling of 1216643 in words is "one million, two hundred sixteen thousand, six hundred forty-three".