1216133465 has 4 divisors (see below), whose sum is σ = 1459360164. Its totient is φ = 972906768.

The previous prime is 1216133453. The next prime is 1216133497. The reversal of 1216133465 is 5643316121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5643316121 = 311 ⋅18145711.

It can be written as a sum of positive squares in 2 ways, for example, as 477815881 + 738317584 = 21859^2 + 27172^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216133465 - 2⁴ = 1216133449 is a prime.

It is a Duffinian 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, 121613342 + ... + 121613351.

It is an arithmetic number, because the mean of its divisors is an integer number (364840041).

Almost surely, 2^1216133465 is an apocalyptic number.

It is an amenable number.

1216133465 is a deficient number, since it is larger than the sum of its proper divisors (243226699).

1216133465 is an equidigital number, since it uses as much as digits as its factorization.

1216133465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243226698.

The product of its digits is 12960, while the sum is 32.

The square root of 1216133465 is about 34873.1051815005. The cubic root of 1216133465 is about 1067.3997083043.

Adding to 1216133465 its reverse (5643316121), we get a palindrome (6859449586).

The spelling of 1216133465 in words is "one billion, two hundred sixteen million, one hundred thirty-three thousand, four hundred sixty-five".