216136566 has 64 divisors (see below), whose sum is σ = 506442240. Its totient is φ = 68191200.

The previous prime is 216136561. The next prime is 216136579. The reversal of 216136566 is 665631612.

216136566 is a `hidden beast` number, since 2 + 1 + 61 + 36 + 566 = 666.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216136566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216136561) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124581 + ... + 126303.

It is an arithmetic number, because the mean of its divisors is an integer number (7913160).

Almost surely, 2^216136566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216136566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (253221120).

216136566 is an abundant number, since it is smaller than the sum of its proper divisors (290305674).

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

216136566 is a wasteful number, since it uses less digits than its factorization.

216136566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1858 (or 1852 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 216136566 is about 14701.5837922314. The cubic root of 216136566 is about 600.1264233600.

The spelling of 216136566 in words is "two hundred sixteen million, one hundred thirty-six thousand, five hundred sixty-six".