1216655 has 12 divisors (see below), whose sum is σ = 1605576. Its totient is φ = 884400.

The previous prime is 1216619. The next prime is 1216681. The reversal of 1216655 is 5566121.

It is not a de Polignac number, because 1216655 - 2⁶ = 1216591 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 401 + ... + 1610.

It is an arithmetic number, because the mean of its divisors is an integer number (133798).

2^1216655 is an apocalyptic number.

1216655 is a deficient number, since it is larger than the sum of its proper divisors (388921).

1216655 is a wasteful number, since it uses less digits than its factorization.

1216655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2038 (or 2027 counting only the distinct ones).

The product of its digits is 1800, while the sum is 26.

The square root of 1216655 is about 1103.0208520241. The cubic root of 1216655 is about 106.7552270164.

It can be divided in two parts, 12166 and 55, that added together give a palindrome (12221).

The spelling of 1216655 in words is "one million, two hundred sixteen thousand, six hundred fifty-five".