1216609 has 3 divisors (see below), whose sum is σ = 1217713. Its totient is φ = 1215506.

The previous prime is 1216603. The next prime is 1216619. The reversal of 1216609 is 9066121.

The square root of 1216609 is 1103.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9066121 = 3011².

It is not a de Polignac number, because 1216609 - 2³ = 1216601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216601) 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 2 ways as a sum of consecutive naturals, for example, 552 + ... + 1654.

2^1216609 is an apocalyptic number.

1216609 is the 1103-rd square number.

1216609 is the 552-nd centered octagonal number.

It is an amenable number.

1216609 is a deficient number, since it is larger than the sum of its proper divisors (1104).

1216609 is an frugal number, since it uses more digits than its factorization.

1216609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2206 (or 1103 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The cubic root of 1216609 is about 106.7538815782.

Multiplying 1216609 by its sum of digits (25), we get a square (30415225 = 5515²).

Multiplying 1216609 by its reverse (9066121), we get a square (11029924403689 = 3321133²).

The spelling of 1216609 in words is "one million, two hundred sixteen thousand, six hundred nine".