1216214989 has 4 divisors (see below), whose sum is σ = 1326780000. Its totient is φ = 1105649980.

The previous prime is 1216214981. The next prime is 1216215041. The reversal of 1216214989 is 9894126121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9894126121 = 11 ⋅899466011.

It is a cyclic number.

It is not a de Polignac number, because 1216214989 - 2³ = 1216214981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216214981) 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, 55282489 + ... + 55282510.

It is an arithmetic number, because the mean of its divisors is an integer number (331695000).

Almost surely, 2^1216214989 is an apocalyptic number.

It is an amenable number.

1216214989 is a deficient number, since it is larger than the sum of its proper divisors (110565011).

1216214989 is a wasteful number, since it uses less digits than its factorization.

1216214989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110565010.

The product of its digits is 62208, while the sum is 43.

The square root of 1216214989 is about 34874.2740282862. The cubic root of 1216214989 is about 1067.4235589621.

The spelling of 1216214989 in words is "one billion, two hundred sixteen million, two hundred fourteen thousand, nine hundred eighty-nine".