1216697887969 has 4 divisors (see below), whose sum is σ = 1219360247044. Its totient is φ = 1214035528896.

The previous prime is 1216697887961. The next prime is 1216697887973. The reversal of 1216697887969 is 9697887966121.

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 924597633600 + 292100254369 = 961560^2 + 540463^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216697887969 - 2³ = 1216697887961 is a prime.

It is a super-2 number, since 2×1216697887969² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216697887961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1331178852 + ... + 1331179765.

It is an arithmetic number, because the mean of its divisors is an integer number (304840061761).

Almost surely, 2^{1216697887969} is an apocalyptic number.

It is an amenable number.

1216697887969 is a deficient number, since it is larger than the sum of its proper divisors (2662359075).

1216697887969 is an equidigital number, since it uses as much as digits as its factorization.

1216697887969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2662359074.

The product of its digits is 987614208, while the sum is 79.

The spelling of 1216697887969 in words is "one trillion, two hundred sixteen billion, six hundred ninety-seven million, eight hundred eighty-seven thousand, nine hundred sixty-nine".