1216665 has 24 divisors (see below), whose sum is σ = 2221440. Its totient is φ = 614304.

The previous prime is 1216619. The next prime is 1216681. The reversal of 1216665 is 5666121.

It is a happy number.

It is not a de Polignac number, because 1216665 - 2⁶ = 1216601 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 144 + ... + 1566.

It is an arithmetic number, because the mean of its divisors is an integer number (92560).

2^1216665 is an apocalyptic number.

1216665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216665 is a deficient number, since it is larger than the sum of its proper divisors (1004775).

1216665 is a wasteful number, since it uses less digits than its factorization.

1216665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1453 (or 1450 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 1216665 is about 1103.0253850207. The cubic root of 1216665 is about 106.7555194984.

It can be divided in two parts, 1216 and 665, that added together give a palindrome (1881).

The spelling of 1216665 in words is "one million, two hundred sixteen thousand, six hundred sixty-five".