1216901533 has 4 divisors (see below), whose sum is σ = 1217045340. Its totient is φ = 1216757728.

The previous prime is 1216901507. The next prime is 1216901537. The reversal of 1216901533 is 3351096121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3351096121 = 199 ⋅16839679.

It can be written as a sum of positive squares in 2 ways, for example, as 1031887129 + 185014404 = 32123^2 + 13602^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216901533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1216901495 and 1216901504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216901537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58360 + ... + 76417.

It is an arithmetic number, because the mean of its divisors is an integer number (304261335).

Almost surely, 2^1216901533 is an apocalyptic number.

It is an amenable number.

1216901533 is a deficient number, since it is larger than the sum of its proper divisors (143807).

1216901533 is an equidigital number, since it uses as much as digits as its factorization.

1216901533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143806.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 1216901533 is about 34884.1157692151. The cubic root of 1216901533 is about 1067.6243719754.

Adding to 1216901533 its reverse (3351096121), we get a palindrome (4567997654).

The spelling of 1216901533 in words is "one billion, two hundred sixteen million, nine hundred one thousand, five hundred thirty-three".