1216611265 has 8 divisors (see below), whose sum is σ = 1460130408. Its totient is φ = 973157760.

The previous prime is 1216611257. The next prime is 1216611283. The reversal of 1216611265 is 5621166121.

It can be written as a sum of positive squares in 4 ways, for example, as 36276529 + 1180334736 = 6023^2 + 34356^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1216611265 - 2³ = 1216611257 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45859 + ... + 67351.

It is an arithmetic number, because the mean of its divisors is an integer number (182516301).

Almost surely, 2^1216611265 is an apocalyptic number.

It is an amenable number.

1216611265 is a deficient number, since it is larger than the sum of its proper divisors (243519143).

1216611265 is a wasteful number, since it uses less digits than its factorization.

1216611265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32819.

The product of its digits is 4320, while the sum is 31.

The square root of 1216611265 is about 34879.9550601775. The cubic root of 1216611265 is about 1067.5394782717.

Adding to 1216611265 its reverse (5621166121), we get a palindrome (6837777386).

The spelling of 1216611265 in words is "one billion, two hundred sixteen million, six hundred eleven thousand, two hundred sixty-five".