216404197 has 2 divisors, whose sum is σ = 216404198. Its totient is φ = 216404196.

The previous prime is 216404161. The next prime is 216404219. The reversal of 216404197 is 791404612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196028001 + 20376196 = 14001^2 + 4514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216404197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216404107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108202098 + 108202099.

It is an arithmetic number, because the mean of its divisors is an integer number (108202099).

Almost surely, 2^216404197 is an apocalyptic number.

It is an amenable number.

216404197 is a deficient number, since it is larger than the sum of its proper divisors (1).

216404197 is an equidigital number, since it uses as much as digits as its factorization.

216404197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 216404197 is about 14710.6830908697. The cubic root of 216404197 is about 600.3740232773.

The spelling of 216404197 in words is "two hundred sixteen million, four hundred four thousand, one hundred ninety-seven".