1216985823 has 16 divisors (see below), whose sum is σ = 1807142400. Its totient is φ = 809433720.

The previous prime is 1216985813. The next prime is 1216985831. The reversal of 1216985823 is 3285896121.

1216985823 is a `hidden beast` number, since 1 + 2 + 1 + 69 + 8 + 582 + 3 = 666.

It is not a de Polignac number, because 1216985823 - 2¹³ = 1216977631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216985813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40653 + ... + 63926.

It is an arithmetic number, because the mean of its divisors is an integer number (112946400).

Almost surely, 2^1216985823 is an apocalyptic number.

1216985823 is a deficient number, since it is larger than the sum of its proper divisors (590156577).

1216985823 is a wasteful number, since it uses less digits than its factorization.

1216985823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105019 (or 105013 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 1216985823 is about 34885.3238912870. The cubic root of 1216985823 is about 1067.6490214583.

The spelling of 1216985823 in words is "one billion, two hundred sixteen million, nine hundred eighty-five thousand, eight hundred twenty-three".