216306109 has 2 divisors, whose sum is σ = 216306110. Its totient is φ = 216306108.

The previous prime is 216306073. The next prime is 216306161. The reversal of 216306109 is 901603612.

216306109 = T₁₂₀₀₇ + T₁₂₀₀₈ + T₁₂₀₀₉.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 141967225 + 74338884 = 11915^2 + 8622^2 .

It is a cyclic number.

It is not a de Polignac number, because 216306109 - 2⁷ = 216305981 is a prime.

It is equal to p_11930392 and since 216306109 and 11930392 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216306179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108153054 + 108153055.

It is an arithmetic number, because the mean of its divisors is an integer number (108153055).

Almost surely, 2^216306109 is an apocalyptic number.

216306109 is the 12009-th centered triangular number.

It is an amenable number.

216306109 is a deficient number, since it is larger than the sum of its proper divisors (1).

216306109 is an equidigital number, since it uses as much as digits as its factorization.

216306109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 216306109 is about 14707.3488093538. The cubic root of 216306109 is about 600.2833004729.

The spelling of 216306109 in words is "two hundred sixteen million, three hundred six thousand, one hundred nine".