216397 has 2 divisors, whose sum is σ = 216398. Its totient is φ = 216396.

The previous prime is 216379. The next prime is 216401. The reversal of 216397 is 793612.

Together with previous prime (216379) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203401 + 12996 = 451^2 + 114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108198 + 108199.

It is an arithmetic number, because the mean of its divisors is an integer number (108199).

2²¹⁶³⁹⁷ is an apocalyptic number.

It is an amenable number.

216397 is a deficient number, since it is larger than the sum of its proper divisors (1).

216397 is an equidigital number, since it uses as much as digits as its factorization.

216397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 28.

The square root of 216397 is about 465.1849094715. The cubic root of 216397 is about 60.0367367615.

The spelling of 216397 in words is "two hundred sixteen thousand, three hundred ninety-seven".