1216350911689 has 3 divisors (see below), whose sum is σ = 1216352014573. Its totient is φ = 1216349808806.

The previous prime is 1216350911683. The next prime is 1216350911731. The reversal of 1216350911689 is 9861190536121.

The square root of 1216350911689 is 1102883.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 1216350911689 - 2¹⁵ = 1216350878921 is a prime.

It is a super-2 number, since 2×1216350911689² (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 (1216350911683) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 551442 + ... + 1654324.

Almost surely, 2^{1216350911689} is an apocalyptic number.

1216350911689 is the 1102883-rd square number.

1216350911689 is the 551442-nd centered octagonal number.

It is an amenable number.

1216350911689 is a deficient number, since it is larger than the sum of its proper divisors (1102884).

1216350911689 is an frugal number, since it uses more digits than its factorization.

1216350911689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2205766 (or 1102883 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 52.

The spelling of 1216350911689 in words is "one trillion, two hundred sixteen billion, three hundred fifty million, nine hundred eleven thousand, six hundred eighty-nine".