1216605655 has 16 divisors (see below), whose sum is σ = 1486315584. Its totient is φ = 955745280.

The previous prime is 1216605653. The next prime is 1216605671. The reversal of 1216605655 is 5565066121.

It is not a de Polignac number, because 1216605655 - 2¹ = 1216605653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216605653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202302 + ... + 208228.

It is an arithmetic number, because the mean of its divisors is an integer number (92894724).

Almost surely, 2^1216605655 is an apocalyptic number.

1216605655 is a deficient number, since it is larger than the sum of its proper divisors (269709929).

1216605655 is an equidigital number, since it uses as much as digits as its factorization.

1216605655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6666.

The product of its (nonzero) digits is 54000, while the sum is 37.

The square root of 1216605655 is about 34879.8746414032. The cubic root of 1216605655 is about 1067.5378374009.

The spelling of 1216605655 in words is "one billion, two hundred sixteen million, six hundred five thousand, six hundred fifty-five".