1216057986 has 144 divisors (see below), whose sum is σ = 3228596280. Its totient is φ = 328204800.

The previous prime is 1216057979. The next prime is 1216058003. The reversal of 1216057986 is 6897506121.

1216057986 is a `hidden beast` number, since 12 + 1 + 60 + 579 + 8 + 6 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 814817025 + 401240961 = 28545^2 + 20031^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 820366 + ... + 821846.

Almost surely, 2^1216057986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216057986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1614298140).

1216057986 is an abundant number, since it is smaller than the sum of its proper divisors (2012538294).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216057986 is a wasteful number, since it uses less digits than its factorization.

1216057986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1553 (or 1539 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 1216057986 is about 34872.0229697103. The cubic root of 1216057986 is about 1067.3776252211.

The spelling of 1216057986 in words is "one billion, two hundred sixteen million, fifty-seven thousand, nine hundred eighty-six".