216690197 has 2 divisors, whose sum is σ = 216690198. Its totient is φ = 216690196.

The previous prime is 216690191. The next prime is 216690209. The reversal of 216690197 is 791096612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216413521 + 276676 = 14711^2 + 526^2 .

It is a cyclic number.

It is not a de Polignac number, because 216690197 - 2²² = 212495893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216690191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108345098 + 108345099.

It is an arithmetic number, because the mean of its divisors is an integer number (108345099).

Almost surely, 2^216690197 is an apocalyptic number.

It is an amenable number.

216690197 is a deficient number, since it is larger than the sum of its proper divisors (1).

216690197 is an equidigital number, since it uses as much as digits as its factorization.

216690197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 216690197 is about 14720.4007078612. The cubic root of 216690197 is about 600.6383918152.

The spelling of 216690197 in words is "two hundred sixteen million, six hundred ninety thousand, one hundred ninety-seven".