1216965789 has 60 divisors (see below), whose sum is σ = 2072584800. Its totient is φ = 709334496.

The previous prime is 1216965787. The next prime is 1216965793. The reversal of 1216965789 is 9875696121.

1216965789 is a `hidden beast` number, since 1 + 2 + 1 + 69 + 6 + 578 + 9 = 666.

It is not a de Polignac number, because 1216965789 - 2¹ = 1216965787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216965781) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 257752 + ... + 262430.

It is an arithmetic number, because the mean of its divisors is an integer number (34543080).

Almost surely, 2^1216965789 is an apocalyptic number.

1216965789 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1216965789 is a deficient number, since it is larger than the sum of its proper divisors (855619011).

1216965789 is a wasteful number, since it uses less digits than its factorization.

1216965789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4736 (or 4714 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 54.

The square root of 1216965789 is about 34885.0367492998. The cubic root of 1216965789 is about 1067.6431628861.

The spelling of 1216965789 in words is "one billion, two hundred sixteen million, nine hundred sixty-five thousand, seven hundred eighty-nine".