1216409 has 4 divisors (see below), whose sum is σ = 1255680. Its totient is φ = 1177140.

The previous prime is 1216393. The next prime is 1216417. The reversal of 1216409 is 9046121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1216409 - 2⁴ = 1216393 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (1216459) 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, 19589 + ... + 19650.

It is an arithmetic number, because the mean of its divisors is an integer number (313920).

2^1216409 is an apocalyptic number.

It is an amenable number.

1216409 is a deficient number, since it is larger than the sum of its proper divisors (39271).

1216409 is an equidigital number, since it uses as much as digits as its factorization.

1216409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39270.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1216409 is about 1102.9093344423. The cubic root of 1216409 is about 106.7480314526.

The spelling of 1216409 in words is "one million, two hundred sixteen thousand, four hundred nine".