1216241165 has 4 divisors (see below), whose sum is σ = 1459489404. Its totient is φ = 972992928.

The previous prime is 1216241141. The next prime is 1216241177. The reversal of 1216241165 is 5611426121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 130736356 + 1085504809 = 11434^2 + 32947^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216241165 - 2¹⁶ = 1216175629 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121624112 + ... + 121624121.

It is an arithmetic number, because the mean of its divisors is an integer number (364872351).

Almost surely, 2^1216241165 is an apocalyptic number.

It is an amenable number.

1216241165 is a deficient number, since it is larger than the sum of its proper divisors (243248239).

1216241165 is an equidigital number, since it uses as much as digits as its factorization.

1216241165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243248238.

The product of its digits is 2880, while the sum is 29.

The square root of 1216241165 is about 34874.6493172333. The cubic root of 1216241165 is about 1067.4312167854.

Adding to 1216241165 its reverse (5611426121), we get a palindrome (6827667286).

The spelling of 1216241165 in words is "one billion, two hundred sixteen million, two hundred forty-one thousand, one hundred sixty-five".