1216605 has 32 divisors (see below), whose sum is σ = 2225664. Its totient is φ = 562176.

The previous prime is 1216603. The next prime is 1216619. The reversal of 1216605 is 5066121.

It is a happy number.

It is not a de Polignac number, because 1216605 - 2¹ = 1216603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216601) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3132 + ... + 3498.

It is an arithmetic number, because the mean of its divisors is an integer number (69552).

2^1216605 is an apocalyptic number.

1216605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216605 is a deficient number, since it is larger than the sum of its proper divisors (1009059).

1216605 is a wasteful number, since it uses less digits than its factorization.

1216605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1216605 is about 1102.9981867619. The cubic root of 1216605 is about 106.7537645819.

The spelling of 1216605 in words is "one million, two hundred sixteen thousand, six hundred five".