1216091255 has 4 divisors (see below), whose sum is σ = 1459309512. Its totient is φ = 972873000.

The previous prime is 1216091251. The next prime is 1216091269. The reversal of 1216091255 is 5521906121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5521906121 = 89 ⋅62043889.

It is not a de Polignac number, because 1216091255 - 2² = 1216091251 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 (1216091251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121609121 + ... + 121609130.

It is an arithmetic number, because the mean of its divisors is an integer number (364827378).

Almost surely, 2^1216091255 is an apocalyptic number.

1216091255 is a deficient number, since it is larger than the sum of its proper divisors (243218257).

1216091255 is an equidigital number, since it uses as much as digits as its factorization.

1216091255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243218256.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1216091255 is about 34872.4999820776. The cubic root of 1216091255 is about 1067.3873589297.

Adding to 1216091255 its reverse (5521906121), we get a palindrome (6737997376).

The spelling of 1216091255 in words is "one billion, two hundred sixteen million, ninety-one thousand, two hundred fifty-five".