1216986289 has 4 divisors (see below), whose sum is σ = 1217167360. Its totient is φ = 1216805220.

The previous prime is 1216986241. The next prime is 1216986299. The reversal of 1216986289 is 9826896121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1216986289 - 2²³ = 1208597681 is a prime.

It is a super-2 number, since 2×1216986289² = 2962111255227983042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216986299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80049 + ... + 94030.

It is an arithmetic number, because the mean of its divisors is an integer number (304291840).

Almost surely, 2^1216986289 is an apocalyptic number.

It is an amenable number.

1216986289 is a deficient number, since it is larger than the sum of its proper divisors (181071).

1216986289 is an equidigital number, since it uses as much as digits as its factorization.

1216986289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181070.

The product of its digits is 746496, while the sum is 52.

The square root of 1216986289 is about 34885.3305703128. The cubic root of 1216986289 is about 1067.6491577306.

The spelling of 1216986289 in words is "one billion, two hundred sixteen million, nine hundred eighty-six thousand, two hundred eighty-nine".