216926209 has 2 divisors, whose sum is σ = 216926210. Its totient is φ = 216926208.

The previous prime is 216926201. The next prime is 216926231. The reversal of 216926209 is 902629612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 163123984 + 53802225 = 12772^2 + 7335^2 .

It is a cyclic number.

It is not a de Polignac number, because 216926209 - 2³ = 216926201 is a prime.

It is a super-2 number, since 2×216926209² = 94113960302223362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (216926201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108463104 + 108463105.

It is an arithmetic number, because the mean of its divisors is an integer number (108463105).

Almost surely, 2^216926209 is an apocalyptic number.

It is an amenable number.

216926209 is a deficient number, since it is larger than the sum of its proper divisors (1).

216926209 is an equidigital number, since it uses as much as digits as its factorization.

216926209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 216926209 is about 14728.4150199538. The cubic root of 216926209 is about 600.8563780388.

The spelling of 216926209 in words is "two hundred sixteen million, nine hundred twenty-six thousand, two hundred nine".