1216631011 has 4 divisors (see below), whose sum is σ = 1217837800. Its totient is φ = 1215424224.

The previous prime is 1216630969. The next prime is 1216631029. The reversal of 1216631011 is 1101366121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1101366121 = 5519 ⋅199559.

It is a cyclic number.

It is not a de Polignac number, because 1216631011 - 2¹⁷ = 1216499939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216631411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 601881 + ... + 603898.

It is an arithmetic number, because the mean of its divisors is an integer number (304459450).

Almost surely, 2^1216631011 is an apocalyptic number.

1216631011 is a deficient number, since it is larger than the sum of its proper divisors (1206789).

1216631011 is a wasteful number, since it uses less digits than its factorization.

1216631011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206788.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 1216631011 is about 34880.2381155863. The cubic root of 1216631011 is about 1067.5452537458.

Adding to 1216631011 its reverse (1101366121), we get a palindrome (2317997132).

The spelling of 1216631011 in words is "one billion, two hundred sixteen million, six hundred thirty-one thousand, eleven".