216921097 has 2 divisors, whose sum is σ = 216921098. Its totient is φ = 216921096.

The previous prime is 216921077. The next prime is 216921109. The reversal of 216921097 is 790129612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213276816 + 3644281 = 14604^2 + 1909^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216921097 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216921077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108460548 + 108460549.

It is an arithmetic number, because the mean of its divisors is an integer number (108460549).

Almost surely, 2^216921097 is an apocalyptic number.

It is an amenable number.

216921097 is a deficient number, since it is larger than the sum of its proper divisors (1).

216921097 is an equidigital number, since it uses as much as digits as its factorization.

216921097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 216921097 is about 14728.2414768363. The cubic root of 216921097 is about 600.8516581513.

The spelling of 216921097 in words is "two hundred sixteen million, nine hundred twenty-one thousand, ninety-seven".