216636109 has 2 divisors, whose sum is σ = 216636110. Its totient is φ = 216636108.

The previous prime is 216636047. The next prime is 216636143. The reversal of 216636109 is 901636612.

It is an a-pointer prime, because the next prime (216636143) can be obtained adding 216636109 to its sum of digits (34).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179694025 + 36942084 = 13405^2 + 6078^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216636109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216636179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108318054 + 108318055.

It is an arithmetic number, because the mean of its divisors is an integer number (108318055).

Almost surely, 2^216636109 is an apocalyptic number.

It is an amenable number.

216636109 is a deficient number, since it is larger than the sum of its proper divisors (1).

216636109 is an equidigital number, since it uses as much as digits as its factorization.

216636109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 216636109 is about 14718.5634149532. The cubic root of 216636109 is about 600.5884125772.

It can be divided in two parts, 21663 and 6109, that added together give a palindrome (27772).

The spelling of 216636109 in words is "two hundred sixteen million, six hundred thirty-six thousand, one hundred nine".