1216511986 has 16 divisors (see below), whose sum is σ = 1848447000. Its totient is φ = 600386688.

The previous prime is 1216511977. The next prime is 1216512029. The reversal of 1216511986 is 6891156121.

It can be written as a sum of positive squares in 4 ways, for example, as 329604025 + 886907961 = 18155^2 + 29781^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 103540 + ... + 114688.

Almost surely, 2^1216511986 is an apocalyptic number.

1216511986 is a deficient number, since it is larger than the sum of its proper divisors (631935014).

1216511986 is a wasteful number, since it uses less digits than its factorization.

1216511986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11853.

The product of its digits is 25920, while the sum is 40.

The square root of 1216511986 is about 34878.5318785066. The cubic root of 1216511986 is about 1067.5104393782.

The spelling of 1216511986 in words is "one billion, two hundred sixteen million, five hundred eleven thousand, nine hundred eighty-six".